Move all z80-dependencies into arch/z80/src/z80

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@683 42af7a65-404d-4744-a932-0658087f49c3

29 files changed, 502 insertions, 253 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 163680686..f08c0ac1a 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -339,4 +339,7 @@
 	* Began adding support for the ZiLOG Z8Encore! microcontroller for the Z8Encore000ZCO
 	  development board and the Z8F642 part.
 	* Fix broken 'clean' target on z80sim configurations
+	* Re-structure arch/z80 to provide support for all ZiLOG 8-bit microcontrollers (ez8
+	  in particular for now).
+
 
diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html
index f1c8b3c59..a3762e77e 100644
--- a/nuttx/Documentation/NuttX.html
+++ b/nuttx/Documentation/NuttX.html
@@ -8,7 +8,7 @@
   <tr align="center" bgcolor="#e4e4e4">
     <td>
       <h1><big><font color="#3c34ec"><i>NuttX RTOS</i></font></big></h1>
-      <p>Last Updated: February 11, 2008</p>
+      <p>Last Updated: February 14, 2008</p>
     </td>
   </tr>
 </table>
@@ -993,6 +993,8 @@ nuttx-0.3.9 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 	* Began adding support for the ZiLOG Z8Encore! microcontroller for the Z8Encore000ZCO
 	  development board and the Z8F642 part.
 	* Fix broken 'clean' target on z80sim configurations
+	* Re-structure arch/z80 to provide support for all ZiLOG 8-bit microcontrollers (ez8
+	  in particular for now).
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/nuttx/TODO b/nuttx/TODO
index 788bab57b..9afd2d112 100644
--- a/nuttx/TODO
+++ b/nuttx/TODO
@@ -1,5 +1,5 @@
-NuttX TODO List (Last updated January 6, 2008)
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+NuttX TODO List (Last updated February 13, 2008)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
   (6)  Task/Scheduler (sched/)
   (1)  Dynamic loader (N/A)
diff --git a/nuttx/arch/z80/include/z8/irq.h b/nuttx/arch/z80/include/z8/irq.h
index 4aaa8752f..15979c0a6 100644
--- a/nuttx/arch/z80/include/z8/irq.h
+++ b/nuttx/arch/z80/include/z8/irq.h
@@ -196,31 +196,79 @@
 
 #define Z8_IRQ_SYSTIMER Z8_TIMER0_IRQ
 
-/* IRQ Stack Frame Format
+/* IRQ State Save Formatt
  *
- * This stack frame is created on each interrupt.  These registers are stored
- * in the TCB to many context switches.
- */
-
-#define XCPT_I               (0) /* Offset 0: Saved I w/interrupt state in carry */
-#define XCPT_BC              (1) /* Offset 1: Saved BC register */
-#define XCPT_IX              (3) /* Offset 3: Saved IX register */
-#define XCPT_IY              (4) /* Offset 4: Saved IY register */
-#define XCPT_SP              (5) /* Offset 5: Offset to SP at time of interrupt */
-#define XCPT_HL              (6) /* Offset 6: Saved HL register */
-#define XCPT_AF              (7) /* Offset 7: Saved AF register */
-#define XCPT_PC              (8) /* Offset 8: Offset to PC at time of interrupt */
-
-#define XCPTCONTEXT_REGS     (9)
-#define XCPTCONTEXT_SIZE     (2 * XCPTCONTEXT_REGS)
-
-/* The ZDS-II provides built-in operations to test & disable and to restore
- * the interrupt state.
+ * These indices describe how the ez8 context is save in the state save array
  *
- * irqstate_t irqsave(void);
- * void irqrestore(irqstate_t flags);
+ * Byte offsets:
  */
 
+#define XCPT8_R0              (0) /* Offset 0-15:  R0-R15 */
+#define XCPT8_R1              (1)
+#define XCPT8_R2              (2)
+#define XCPT8_R3              (3)
+#define XCPT8_R4              (4)
+#define XCPT8_R5              (5)
+#define XCPT8_R6              (6)
+#define XCPT8_R7              (7)
+#define XCPT8_R8              (8)
+#define XCPT8_R9              (9)
+#define XCPT8_R10            (10)
+#define XCPT8_R11            (11)
+#define XCPT8_R12            (12)
+#define XCPT8_R13            (13)
+#define XCPT8_R14            (14)
+#define XCPT8_R15            (15)
+#define XCPT8_SPH            (16) /* Offset 16: SP[8:15] */
+#define XCPT8_SPL            (17) /* Offset 17: SP[0:7] */
+#define XCPT8_RP             (18) /* Offset 18: Register pointer */
+#define XCPT8_FLAGS          (19) /* Offset 19: FLAGS */
+#define XCPT8_PCH            (20) /* Offset 20: PC[8:15] */
+#define XCPT8_PCL            (21) /* Offset 21: PC[0:7] */
+
+/* 16-bit "word" offsets */
+
+#define XCPT_RR0              (0) /* Indices 0-7:  RR0-RR14 */
+#define XCPT_RR2              (1)
+#define XCPT_RR4              (2)
+#define XCPT_RR6              (3)
+#define XCPT_RR8              (4)
+#define XCPT_RR10             (5)
+#define XCPT_RR12             (6)
+#define XCPT_R1R4             (7)
+#define XCPT_SP               (8) /* Index 8: SP[8:15] */
+#define XCPT_I                (9) /* Index 9: FLAGS */
+#define XCPT_PC              (10) /* Index 10: PC[8:15] */
+
+#define XCPTCONTEXT_REGS     (11)
+
+/* Byte offsets: */
+
+#define XCPT_R0_OFFS         (2*XCPT_RR0)      /* Offset 0-15:  R0-R15 */
+#define XCPT_R1_OFFS         (2*XCPT_RR0+1)
+#define XCPT_R2_OFFS         (2*XCPT_RR2)
+#define XCPT_R3_OFFS         (2*XCPT_RR2+1)
+#define XCPT_R4_OFFS         (2*XCPT_RR4)
+#define XCPT_R5_OFFS         (2*XCPT_RR4+1)
+#define XCPT_R6_OFFS         (2*XCPT_RR6)
+#define XCPT_R7_OFFS         (2*XCPT_RR6+1)
+#define XCPT_R8_OFFS         (2*XCPT_RR8)
+#define XCPT_R9_OFFS         (2*XCPT_RR8+1)
+#define XCPT_R10_OFFS        (2*XCPT_RR10)
+#define XCPT_R11_OFFS        (2*XCPT_RR10+1)
+#define XCPT_R12_OFFS        (2*XCPT_RR12)
+#define XCPT_R13_OFFS        (2*XCPT_RR12+1)
+#define XCPT_R14_OFFS        (2*XCPT_R1R4)
+#define XCPT_R15_OFFS        (2*XCPT_R1R4+1)
+#define XCPT_SPH_OFFS        (2*XCPT_SP)       /* Offset 16: SP[8:15] */
+#define XCPT_SPL_OFFS        (2*XCPT_SP+1)     /* Offset 17: SP[0:7] */
+#define XCPT_RP_OFFS         (2*XCPT_I)        /* Offset 18: Register pointer */
+#define XCPT_FLAGS_OFFS      (2*XCPT_I+1)      /* Offset 19: FLAGS */
+#define XCPT_PCH_OFFS        (2*XCPT_PC)       /* Offset 20: PC[8:15] */
+#define XCPT_PCL_OFFS        (2*XCPT_PC+1)     /* Offset 21: PC[0:7] */
+
+#define XCPTCONTEXT_SIZE     (2*XCPTCONTEXT_REGS)
+
 /****************************************************************************
  * Public Types
  ****************************************************************************/
@@ -237,7 +285,7 @@ struct xcptcontext
 {
   /* Register save area */
 
-  uint16 regs[XCPTCONTEXT_REGS];
+  chipreg_t regs[XCPTCONTEXT_REGS];
 
   /* The following function pointer is non-zero if there
    * are pending signals to be processed.
diff --git a/nuttx/arch/z80/include/z80/irq.h b/nuttx/arch/z80/include/z80/irq.h
index f71ed208e..25d43e363 100644
--- a/nuttx/arch/z80/include/z80/irq.h
+++ b/nuttx/arch/z80/include/z80/irq.h
@@ -98,14 +98,14 @@ struct xcptcontext
 {
   /* Register save area */
 
-  uint16 regs[XCPTCONTEXT_REGS];
+  chipreg_t regs[XCPTCONTEXT_REGS];
 
   /* The following function pointer is non-zero if there
    * are pending signals to be processed.
    */
 
 #ifndef CONFIG_DISABLE_SIGNALS
-  void *sigdeliver; /* Actual type is sig_deliver_t */
+  CODE void *sigdeliver; /* Actual type is sig_deliver_t */
 
   /* The following retains that state during signal execution */
 
diff --git a/nuttx/arch/z80/src/common/up_assert.c b/nuttx/arch/z80/src/common/up_assert.c
index d7243e716..1d8fd6a5a 100644
--- a/nuttx/arch/z80/src/common/up_assert.c
+++ b/nuttx/arch/z80/src/common/up_assert.c
@@ -137,7 +137,7 @@ void up_assert(void)
 #endif
 
   up_stackdump();
-  up_registerdump();
+  REGISTER_DUMP();
  _up_assert(EXIT_FAILURE);
 }
 
@@ -174,6 +174,6 @@ void up_assert_code(int errorcode)
 #endif
 
   up_stackdump();
-  up_registerdump();
+  REGISTER_DUMP();
  _up_assert(errorcode);
 }
diff --git a/nuttx/arch/z80/src/common/up_blocktask.c b/nuttx/arch/z80/src/common/up_blocktask.c
index e2d405b36..d0e792203 100644
--- a/nuttx/arch/z80/src/common/up_blocktask.c
+++ b/nuttx/arch/z80/src/common/up_blocktask.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_blocktask.c
+ * arch/z80/src/common/up_blocktask.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -45,6 +45,7 @@
 
 #include <nuttx/arch.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -128,7 +129,7 @@ void up_block_task(FAR _TCB *tcb, tstate_t task_state)
         {
           /* Are we in an interrupt handler? */
 
-          if (IN_INTERRUPT)
+          if (IN_INTERRUPT())
             {
               /* Yes, then we have to do things differently.
                * Just copy the current registers into the OLD rtcb.
diff --git a/nuttx/arch/z80/src/common/up_doirq.c b/nuttx/arch/z80/src/common/up_doirq.c
index 9e9105426..f9c9f72bb 100644
--- a/nuttx/arch/z80/src/common/up_doirq.c
+++ b/nuttx/arch/z80/src/common/up_doirq.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_doirq.c
+ * arch/z80/src/common/up_doirq.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -38,11 +38,15 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
 #include <sys/types.h>
-#include <nuttx/irq.h>
-#include <nuttx/arch.h>
 #include <assert.h>
 #include "up_arch.h"
+
+#include <nuttx/irq.h>
+#include <nuttx/arch.h>
+
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -66,39 +70,37 @@
  * Public Functions
  ****************************************************************************/
 
-void up_doirq(int irq, chipreg_t *regs)
+FAR chipreg_t *up_doirq(ubyte irq, FAR chipreg_t *regs)
 {
   up_ledon(LED_INIRQ);
+
 #ifdef CONFIG_SUPPRESS_INTERRUPTS
+
+  lib_lowprintf("Unexpected IRQ\n");
+  IRQ_ENTER(regs);
   PANIC(OSERR_ERREXCEPTION);
+  return NULL; /* Won't get here */
+
 #else
-  if ((unsigned)irq < NR_IRQS)
+  if (irq < NR_IRQS)
     {
-       /* Current regs non-zero indicates that we are processing
-        * an interrupt; current_regs is also used to manage
-        * interrupt level context switches.
-        */
-
-       current_regs = regs;
-
-       /* Mask and acknowledge the interrupt */
+       /* Indicate that we have enter IRQ processing logic */
 
-       up_maskack_irq(irq);
+       IRQ_ENTER(irq, regs);
 
        /* Deliver the IRQ */
 
        irq_dispatch(irq, regs);
 
-       /* Indicate that we are no long in an interrupt handler */
+       /* If a context switch occurred, 'regs' will hold the new context */
 
-       current_regs = NULL;
+       regs = IRQ_STATE();
 
-       /* Unmask the last interrupt (global interrupts are still
-        * disabled.
-        */
+       /* Indicate that we are no long in interrupt processing logic */
 
-       up_enable_irq(irq);
+       IRQ_LEAVE(irq);
     }
   up_ledoff(LED_INIRQ);
+  return regs;
 #endif
 }
diff --git a/nuttx/arch/z80/src/common/up_initialize.c b/nuttx/arch/z80/src/common/up_initialize.c
index 40205133b..036e4618a 100644
--- a/nuttx/arch/z80/src/common/up_initialize.c
+++ b/nuttx/arch/z80/src/common/up_initialize.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_initialize.c
+ * arch/z80/src/common/up_initialize.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -47,6 +47,7 @@
 #include <nuttx/mm.h>
 #include <arch/board/board.h>
 
+#include "chip/switch.h"
 #include "up_internal.h"
 
 /****************************************************************************
@@ -61,13 +62,6 @@
  * Public Data
  ****************************************************************************/
 
-/* This holds a references to the current interrupt level
- * register storage structure.  If is non-NULL only during
- * interrupt processing.
- */
-
-uint16 *current_regs;
-
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -130,7 +124,7 @@ void up_initialize(void)
 {
   /* Initialize global variables */
 
-  current_regs = NULL;
+  INIT_IRQCONTEXT();
 
   /* Calibrate the timing loop */
 
diff --git a/nuttx/arch/z80/src/common/up_internal.h b/nuttx/arch/z80/src/common/up_internal.h
index e90bec766..838b4cf36 100644
--- a/nuttx/arch/z80/src/common/up_internal.h
+++ b/nuttx/arch/z80/src/common/up_internal.h
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_internal.h
+ * arch/z80/src/common/up_internal.h
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -37,14 +37,7 @@
 #define __UP_INTERNAL_H
 
 /****************************************************************************
- * Included Files
- ****************************************************************************/
-
-#include <arch/irq.h>
-#include "chip/chip.h"
-
-/****************************************************************************
- * Definitions
+ * Conditional Compilation
  ****************************************************************************/
 
 /* Bring-up debug configurations.  These are here (vs defconfig)
@@ -58,69 +51,52 @@
 #undef  CONFIG_SUPPRESS_UART_CONFIG   /* Do not reconfig UART */
 #undef  CONFIG_DUMP_ON_EXIT           /* Dump task state on exit */
 
-/* Macros for portability */
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
 
-#define IN_INTERRUPT             (current_regs != NULL)
-#define SAVE_IRQCONTEXT(tcb)     up_copystate((tcb)->xcp.regs, current_regs)
-#define SET_IRQCONTEXT(tcb)      up_copystate(current_regs, (tcb)->xcp.regs)
-#define SAVE_USERCONTEXT(tcb)    up_saveusercontext((tcb)->xcp.regs)
-#define RESTORE_USERCONTEXT(tcb) up_restoreusercontext((tcb)->xcp.regs)
-#define SIGNAL_RETURN(regs)      up_restoreusercontext(regs)
+#include <arch/irq.h>
+#include "chip/chip.h"
+#include "chip/switch.h"
 
 /****************************************************************************
- * Public Types
+ * Definitions
  ****************************************************************************/
 
-#ifndef __ASSEMBLY__
-typedef void (*up_vector_t)(void);
-#endif
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
 
 /****************************************************************************
  * Public Variables
  ****************************************************************************/
 
-#ifndef __ASSEMBLY__
-/* This holds a references to the current interrupt level
- * register storage structure.  If is non-NULL only during
- * interrupt processing.
- */
-
-extern uint16 *current_regs;
-#endif
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
 
 #ifndef __ASSEMBLY__
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
 
-/* Defined in up_copystate.c */
-
-extern void up_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src);
-
-/* Defined in up_saveusercontext.asm */
-
-extern int up_saveusercontext(chipreg_t *regs);
-
-/* Defined in up_restoreusercontext.asm */
-
-extern int up_restoreusercontext(chipreg_t *regs);
-
-/* Supplied by board-specific logic */
+/* Supplied by chip- or board-specific logic */
 
-extern FAR chipreg_t *up_decodeirq(uint8 rstno, FAR chipreg_t *regs);
-extern void up_irqinitialize(void);
-extern int  up_timerisr(int irq, FAR chipreg_t *regs);
-extern void up_lowputc(char ch) naked_function;
-extern char up_lowgetc(void) naked_function;
+EXTERN void up_irqinitialize(void);
+EXTERN int  up_timerisr(int irq, FAR chipreg_t *regs);
+EXTERN void up_lowputc(char ch) naked_function;
+EXTERN char up_lowgetc(void) naked_function;
 
 /* Defined in up_doirq.c */
 
-extern void up_doirq(int irq, FAR chipreg_t *regs);
+EXTERN FAR chipreg_t *up_doirq(ubyte irq, FAR chipreg_t *regs);
 
 /* Define in up_sigdeliver */
 
-extern void up_sigdeliver(void);
+EXTERN void up_sigdeliver(void);
 
 /* Defined in up_allocateheap.c */
 
@@ -131,8 +107,8 @@ void up_addregion(void);
 /* Defined in up_serial.c */
 
 #if CONFIG_NFILE_DESCRIPTORS > 0
-extern void up_earlyserialinit(void);
-extern void up_serialinit(void);
+EXTERN void up_earlyserialinit(void);
+EXTERN void up_serialinit(void);
 #else
 # define up_earlyserialinit()
 # define up_serialinit()
@@ -140,14 +116,14 @@ extern void up_serialinit(void);
 
 /* Defined in up_timerisr.c */
 
-extern void up_timerinit(void);
+EXTERN void up_timerinit(void);
 
 /* Defined in board/up_leds.c */
 
 #ifdef CONFIG_ARCH_LEDS
-extern void up_ledinit(void);
-extern void up_ledon(int led);
-extern void up_ledoff(int led);
+EXTERN void up_ledinit(void);
+EXTERN void up_ledon(int led);
+EXTERN void up_ledoff(int led);
 #else
 # define up_ledinit()
 # define up_ledon(led)
@@ -157,25 +133,29 @@ extern void up_ledoff(int led);
 /* Defined in board/up_network.c */
 
 #ifdef CONFIG_NET
-extern void up_netinitialize(void);
+EXTERN void up_netinitialize(void);
 #else
 # define up_netinitialize()
 #endif
 
 /* Return the current value of the stack pointer (used in stack dump logic) */
 
-extern uint16 up_getsp(void);
+EXTERN uint16 up_getsp(void);
 
 /* Dump stack and registers */
 
 #ifdef CONFIG_ARCH_STACKDUMP
-extern void up_stackdump(void);
-extern void up_registerdump(void);
+EXTERN void up_stackdump(void);
+# define REGISTER_DUMP() _REGISTER_DUMP()
 #else
 # define up_stackdump()
-# define up_registerdump()
+# define REGISTER_DUMP()
 #endif
 
-#endif /* __ASSEMBLY__ */
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+#endif
 
 #endif  /* __UP_INTERNAL_H */
diff --git a/nuttx/arch/z80/src/common/up_interruptcontext.c b/nuttx/arch/z80/src/common/up_interruptcontext.c
index 6e9e752c9..354227cc2 100644
--- a/nuttx/arch/z80/src/common/up_interruptcontext.c
+++ b/nuttx/arch/z80/src/common/up_interruptcontext.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_interruptcontext.c
+ * arch/z80/src/common/up_interruptcontext.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -38,9 +38,13 @@
  ****************************************************************************/
 
 #include <nuttx/config.h>
+
 #include <sys/types.h>
+
 #include <nuttx/arch.h>
 #include <nuttx/irq.h>
+
+#include "chip/switch.h"
 #include "up_internal.h"
 
 /****************************************************************************
@@ -64,5 +68,5 @@
 
 boolean up_interrupt_context(void)
 {
-   return current_regs != NULL;
+   return IN_INTERRUPT();
 }
diff --git a/nuttx/arch/z80/src/common/up_releasepending.c b/nuttx/arch/z80/src/common/up_releasepending.c
index 853cc7350..e4048152f 100644
--- a/nuttx/arch/z80/src/common/up_releasepending.c
+++ b/nuttx/arch/z80/src/common/up_releasepending.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_releasepending.c
+ * arch/z80/src/common/up_releasepending.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -46,6 +46,7 @@
 #include <nuttx/arch.h>
 
 #include "chip/chip.h"
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -92,7 +93,7 @@ void up_release_pending(void)
        * interrupt context:
        */
 
-      if (IN_INTERRUPT)
+      if (IN_INTERRUPT())
         {
           /* Yes, then we have to do things differently.
            * Just copy the current context into the OLD rtcb.
diff --git a/nuttx/arch/z80/src/common/up_reprioritizertr.c b/nuttx/arch/z80/src/common/up_reprioritizertr.c
index 3adf33735..4576852ac 100644
--- a/nuttx/arch/z80/src/common/up_reprioritizertr.c
+++ b/nuttx/arch/z80/src/common/up_reprioritizertr.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_reprioritizertr.c
+ * arch/z80/src/common/up_reprioritizertr.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -46,6 +46,7 @@
 #include <nuttx/arch.h>
 
 #include "chip/chip.h"
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -140,7 +141,7 @@ void up_reprioritize_rtr(FAR _TCB *tcb, ubyte priority)
 
           /* Are we in an interrupt handler? */
 
-          if (IN_INTERRUPT)
+          if (IN_INTERRUPT())
             {
               /* Yes, then we have to do things differently.
                * Just copy the current context into the OLD rtcb.
diff --git a/nuttx/arch/z80/src/common/up_schedulesigaction.c b/nuttx/arch/z80/src/common/up_schedulesigaction.c
index 946ba859b..bad83e551 100644
--- a/nuttx/arch/z80/src/common/up_schedulesigaction.c
+++ b/nuttx/arch/z80/src/common/up_schedulesigaction.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_schedulesigaction.c
+ * arch/z80/src/common/up_schedulesigaction.c
  *
  *   Copyright (C) 2007,2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -46,6 +46,7 @@
 #include <nuttx/arch.h>
 #include <arch/irq.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -102,11 +103,11 @@
 
 void up_schedule_sigaction(FAR _TCB *tcb, sig_deliver_t sigdeliver)
 {
-  /* Refuse to handle nested signal actions */
-
   dbg("tcb=0x%p sigdeliver=0x%04x\n", tcb, (uint16)sigdeliver);
 
-  if (!tcb->xcp.sigdeliver)
+  /* Refuse to handle nested signal actions */
+
+  if (!SIGNAL_DELIVERING(tcb))
     {
       irqstate_t flags;
 
@@ -114,80 +115,53 @@ void up_schedule_sigaction(FAR _TCB *tcb, sig_deliver_t sigdeliver)
 
       flags = irqsave();
 
-      /* First, handle some special cases when the signal is
-       * being delivered to the currently executing task.
+      /* First, handle some special cases when the signal is being delivered
+       * to the currently executing task.
        */
 
-      dbg("rtcb=0x%p current_regs=0x%p\n", g_readytorun.head, current_regs);
-
       if (tcb == (FAR _TCB*)g_readytorun.head)
         {
-          /* CASE 1:  We are not in an interrupt handler and
-           * a task is signalling itself for some reason.
+          /* CASE 1:  We are not in an interrupt handler and a task is
+           * signalling itself for some reason.
            */
 
-          if (!current_regs)
+          if (!IN_INTERRUPT())
             {
               /* In this case just deliver the signal now. */
 
               sigdeliver(tcb);
             }
 
-          /* CASE 2:  We are in an interrupt handler AND the
-           * interrupted task is the same as the one that
-           * must receive the signal, then we will have to modify
-           * the return state as well as the state in the TCB.
+          /* CASE 2:  We are in an interrupt handler AND the interrupted task
+           * is the same as the one that must receive the signal, then we
+           * will have to modify the return state as well as the state in
+           * the TCB.
            */
 
           else
             {
-              /* Save the return address and interrupt state.
-               * These will be restored by the signal trampoline after
-               * the signals have been delivered.
-               */
+              /* Set up to vector to the trampoline with interrupts disabled. */
 
-              tcb->xcp.sigdeliver    = sigdeliver;
-              tcb->xcp.saved_pc      = current_regs[XCPT_PC];
-              tcb->xcp.saved_i       = current_regs[XCPT_I];
-
-              /* Then set up to vector to the trampoline with interrupts
-               * disabled
-               */
-
-              current_regs[XCPT_PC]  = (uint16)up_sigdeliver;
-              current_regs[XCPT_I]   = 0;
+              SIGNAL_SETUP(tcb, sigdeliver, IRQ_STATE());
 
               /* And make sure that the saved context in the TCB
                * is the same as the interrupt return context.
                */
 
-              up_copystate(tcb->xcp.regs, current_regs);
+              SAVE_IRQCONTEXT(tcb);
             }
         }
 
-      /* Otherwise, we are (1) signaling a task is not running
-       * from an interrupt handler or (2) we are not in an
-       * interrupt handler and the running task is signalling
-       * some non-running task.
+      /* Otherwise, we are (1) signaling a task is not running from an interrupt
+       * handler or (2) we are not in an interrupt handler and the running task
+       * is signalling some non-running task.
        */
 
       else
         {
-          /* Save the return lr and cpsr and one scratch register
-           * These will be restored by the signal trampoline after
-           * the signals have been delivered.
-           */
-
-          tcb->xcp.sigdeliver    = sigdeliver;
-          tcb->xcp.saved_pc      = tcb->xcp.regs[XCPT_PC];
-          tcb->xcp.saved_i       = tcb->xcp.regs[XCPT_I];
-
-          /* Then set up to vector to the trampoline with interrupts
-           * disabled
-           */
+          /* Set up to vector to the trampoline with interrupts disabled. */
 
-          tcb->xcp.regs[XCPT_PC] = (uint16)up_sigdeliver;
-          tcb->xcp.regs[XCPT_I]  = 0;
+          SIGNAL_SETUP(tcb, sigdeliver, tcb->xcp.regs)
         }
 
       irqrestore(flags);
diff --git a/nuttx/arch/z80/src/common/up_sigdeliver.c b/nuttx/arch/z80/src/common/up_sigdeliver.c
index 757e5020b..9ab8f8447 100644
--- a/nuttx/arch/z80/src/common/up_sigdeliver.c
+++ b/nuttx/arch/z80/src/common/up_sigdeliver.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_sigdeliver.c
+ * arch/z80/src/common/up_sigdeliver.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -46,6 +46,7 @@
 #include <nuttx/irq.h>
 #include <nuttx/arch.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -100,7 +101,7 @@ void up_sigdeliver(void)
 
   /* Save the real return state on the stack. */
 
-  up_copystate(regs, rtcb->xcp.regs);
+  COPYSTATE(regs, rtcb->xcp.regs);
   regs[XCPT_PC] = rtcb->xcp.saved_pc;
   regs[XCPT_I]  = rtcb->xcp.saved_i;
 
diff --git a/nuttx/arch/z80/src/common/up_unblocktask.c b/nuttx/arch/z80/src/common/up_unblocktask.c
index 1ce672a5d..aa09342c6 100644
--- a/nuttx/arch/z80/src/common/up_unblocktask.c
+++ b/nuttx/arch/z80/src/common/up_unblocktask.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_unblocktask.c
+ * arch/z80/src/common/up_unblocktask.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -46,6 +46,7 @@
 #include <nuttx/arch.h>
 
 #include "chip/chip.h"
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "clock_internal.h"
 #include "up_internal.h"
@@ -121,7 +122,7 @@ void up_unblock_task(FAR _TCB *tcb)
            * Are we in an interrupt handler? 
            */
 
-          if (IN_INTERRUPT)
+          if (IN_INTERRUPT())
             {
               /* Yes, then we have to do things differently.
                * Just copy the current context into the OLD rtcb.
diff --git a/nuttx/arch/z80/src/z8/Make.defs b/nuttx/arch/z80/src/z8/Make.defs
index 389d6bb81..da6d78a9e 100644
--- a/nuttx/arch/z80/src/z8/Make.defs
+++ b/nuttx/arch/z80/src/z8/Make.defs
@@ -39,11 +39,10 @@ CMN_SSRCS	=
 CMN_CSRCS	= up_initialize.c up_allocateheap.c up_createstack.c \
 		  up_releasestack.c up_interruptcontext.c up_blocktask.c \
 		  up_unblocktask.c up_exit.c up_releasepending.c \
-		  up_reprioritizertr.c up_copystate.c up_idle.c \
-		  up_assert.c up_mdelay.c up_udelay.c \
-		  up_schedulesigaction.c up_sigdeliver.c \
-		  up_registerdump.c up_usestack.c
+		  up_reprioritizertr.c up_idle.c up_assert.c up_doirq.c \
+		  up_mdelay.c up_udelay.c up_schedulesigaction.c \
+		  up_sigdeliver.c up_usestack.c
 
 CHIP_SSRCS	= z8_vector.S #z8_saveusercontext.S z8_restoreusercontext.S
-CHIP_CSRCS	= #z8_initialstate.c z8_irq.c
+CHIP_CSRCS	= #z8_initialstate.c z8_irq.c z8_copystate.c z8_registerdump.c
 
diff --git a/nuttx/arch/z80/src/z8/z8_copystate.c b/nuttx/arch/z80/src/z8/z8_copystate.c
new file mode 100644
index 000000000..d4d4601a8
--- /dev/null
+++ b/nuttx/arch/z80/src/z8/z8_copystate.c
@@ -0,0 +1,79 @@
+/****************************************************************************
+ * arch/z80/src/z8/z8_copystate.c
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <arch/irq.h>
+
+#include "chip/switch.h"
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: z80_copystate
+ ****************************************************************************/
+
+/* Maybe a little faster than most memcpy's */
+
+void z8_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src)
+{
+  int i;
+  for (i = 0; i < XCPTCONTEXT_REGS; i++)
+    {
+      *dest++ = *src++;
+    }
+}
+
diff --git a/nuttx/arch/z80/src/z80/Make.defs b/nuttx/arch/z80/src/z80/Make.defs
index 11b0312f9..18c6bca72 100644
--- a/nuttx/arch/z80/src/z80/Make.defs
+++ b/nuttx/arch/z80/src/z80/Make.defs
@@ -39,10 +39,10 @@ CMN_ASRCS	=
 CMN_CSRCS	= up_initialize.c up_allocateheap.c up_createstack.c \
 		  up_releasestack.c up_interruptcontext.c up_blocktask.c  \
 		  up_unblocktask.c up_exit.c up_releasepending.c \
-		  up_reprioritizertr.c up_copystate.c up_idle.c \
-		  up_assert.c up_mdelay.c up_udelay.c up_schedulesigaction.c \
-		  up_sigdeliver.c up_registerdump.c up_usestack.c
+		  up_reprioritizertr.c up_idle.c up_assert.c up_doirq.c \
+		  up_mdelay.c up_udelay.c up_schedulesigaction.c \
+		  up_sigdeliver.c up_usestack.c
 
 CHIP_ASRCS	= z80_saveusercontext.asm z80_restoreusercontext.asm
-CHIP_CSRCS	= z80_initialstate.c z80_irq.c
+CHIP_CSRCS	= z80_initialstate.c z80_irq.c z80_copystate.c z80_registerdump.c
 
diff --git a/nuttx/arch/z80/src/z80/switch.h b/nuttx/arch/z80/src/z80/switch.h
new file mode 100644
index 000000000..c0c689dbf
--- /dev/null
+++ b/nuttx/arch/z80/src/z80/switch.h
@@ -0,0 +1,168 @@
+/************************************************************************************
+ * arch/z80/src/z80/switch.h
+ * arch/z80/src/chip/switch.h
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ************************************************************************************/
+
+#ifndef __Z80_SWITCH_H
+#define __Z80_SWITCH_H
+
+/************************************************************************************
+ * Included Files
+ ************************************************************************************/
+
+#include <sys/types.h>
+#include <nuttx/sched.h>
+#include <nuttx/arch.h>
+#include "up_internal.h"
+
+/************************************************************************************
+ * Definitions
+ ************************************************************************************/
+
+/* Macros for portability */
+
+/* Initialize the IRQ state */
+
+#define INIT_IRQCONTEXT()        current_regs = NULL
+
+/* IN_INTERRUPT returns TRUE if the system is current operating in the interrupt
+ * context.  IN_INTERRUPT is the inline equivalent of up_interrupt_context().
+ */
+
+#define IN_INTERRUPT()           (current_regs != NULL)
+
+/* The following macro is used when the system enters interrupt handling logic */
+
+#define IRQ_ENTER(irq, regs)     current_regs = (regs)
+
+/* The following macro is used when the system exits interrupt handling logic */
+
+#define IRQ_LEAVE(irq)           current_regs = NULL
+
+/* The following macro is used to sample the interrupt state (as a opaque handle) */
+
+#define IRQ_STATE()              (current_regs)
+
+/* Copy a register state save structure to another location */
+
+#define COPYSTATE(r1,r2)         z80_copystate(r1,r2)
+
+/* Save the current IRQ context in the specified TCB */
+
+#define SAVE_IRQCONTEXT(tcb)     COPYSTATE((tcb)->xcp.regs, current_regs)
+
+/* Set the current IRQ context to the state specified in the TCB */
+
+#define SET_IRQCONTEXT(tcb)      COPYSTATE(current_regs, (tcb)->xcp.regs)
+
+/* Save the user context in the specified TCB.  User context saves can be simpler
+ * because only those registers normally saved in a C called need be stored.
+ */
+
+#define SAVE_USERCONTEXT(tcb)    z80_saveusercontext((tcb)->xcp.regs)
+
+/* Restore the full context -- either a simple user state save or the full,
+ * IRQ state save.
+ */
+
+#define RESTORE_USERCONTEXT(tcb) z80_restoreusercontext((tcb)->xcp.regs)
+
+/* Verify that we have a signal handler */
+
+#define SIGNAL_DELIVERING(tcb)   (tcb->xcp.sigdeliver != NULL)
+
+/* Setup the signal handler trampoline */
+
+#define SIGNAL_SETUP(tcb, sigdeliver, regs)  z80_sigsetup(tcb, sigdeliver, regs)
+
+/* Return from a signal handler using the provided register context */
+
+#define SIGNAL_RETURN(regs)      z80_restoreusercontext(regs)
+
+/* Dump the current machine registers */
+
+#define _REGISTER_DUMP()         z80_registerdump()
+
+/************************************************************************************
+ * Public Variables
+ ************************************************************************************/
+
+#ifndef __ASSEMBLY__
+/* This holds a references to the current interrupt level
+ * register storage structure.  If is non-NULL only during
+ * interrupt processing.
+ */
+
+extern chipreg_t *current_regs;
+#endif
+
+/************************************************************************************
+ * Public Function Prototypes
+ ************************************************************************************/
+
+#ifndef __ASSEMBLY__
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C" {
+#else
+#define EXTERN extern
+#endif
+
+/* Defined in z80_copystate.c */
+
+EXTERN void z80_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src);
+
+/* Defined in z80_saveusercontext.asm */
+
+EXTERN int z80_saveusercontext(FAR chipreg_t *regs);
+
+/* Defined in z80_restoreusercontext.asm */
+
+EXTERN int z80_restoreusercontext(FAR chipreg_t *regs);
+
+/* Defined in z80_sigsetup.c */
+
+EXTERN void z80_sigsetup(FAR _TCB *tcb, sig_deliver_t sigdeliver, FAR chipreg_t *regs);
+
+/* Defined in z80_registerdump.c */
+
+EXTERN void z80_registerdump(void);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+#endif
+
+#endif  /* __Z80_SWITCH_H */
diff --git a/nuttx/arch/z80/src/common/up_copystate.c b/nuttx/arch/z80/src/z80/z80_copystate.c
index b05ab82c3..02dd4841c 100644
--- a/nuttx/arch/z80/src/common/up_copystate.c
+++ b/nuttx/arch/z80/src/z80/z80_copystate.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_copystate.c
+ * arch/z80/src/z80/z80_copystate.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -42,6 +42,7 @@
 #include <sys/types.h>
 #include <arch/irq.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -62,12 +63,12 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: up_undefinedinsn
+ * Name: z80_copystate
  ****************************************************************************/
 
 /* Maybe a little faster than most memcpy's */
 
-void up_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src)
+void z80_copystate(FAR chipreg_t *dest, FAR const chipreg_t *src)
 {
   int i;
   for (i = 0; i < XCPTCONTEXT_REGS; i++)
diff --git a/nuttx/arch/z80/src/z80/z80_head.asm b/nuttx/arch/z80/src/z80/z80_head.asm
index 2a02cdf1c..eb246b588 100644
--- a/nuttx/arch/z80/src/z80/z80_head.asm
+++ b/nuttx/arch/z80/src/z80/z80_head.asm
@@ -61,7 +61,7 @@
 ;**************************************************************************

 

 	.globl	_os_start		; OS entry point

-	.globl	_up_decodeirq		; Interrupt decoding logic

+	.globl	_up_doirq		; Interrupt decoding logic

 

 ;**************************************************************************

 ; Reset entry point

@@ -216,7 +216,7 @@ _up_rstcommon::
 	push	hl			; Place argument #2 at the top of stack

 	push	bc			; Argument #1 is the Reset number

 	inc	sp			; (make byte sized)

-	call	_up_decodeirq		; Decode the IRQ

+	call	_up_doirq		; Decode the IRQ

 

 	; On return, HL points to the beginning of the reg structure to restore

 	; Note that (1) the arguments pushed on the stack are not popped, and (2) the

diff --git a/nuttx/arch/z80/src/z80/z80_irq.c b/nuttx/arch/z80/src/z80/z80_irq.c
index 5d4e92fe0..d9aee3994 100644
--- a/nuttx/arch/z80/src/z80/z80_irq.c
+++ b/nuttx/arch/z80/src/z80/z80_irq.c
@@ -51,6 +51,16 @@
  ****************************************************************************/
 
 /****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/* This holds a references to the current interrupt level register storage
+* structure.  If is non-NULL only during interrupt processing.
+ */
+
+chipreg_t *current_regs;
+
+/****************************************************************************
  * Private Data
  ****************************************************************************/
 
diff --git a/nuttx/arch/z80/src/common/up_registerdump.c b/nuttx/arch/z80/src/z80/z80_registerdump.c
index 05761bf85..8646fcb84 100644
--- a/nuttx/arch/z80/src/common/up_registerdump.c
+++ b/nuttx/arch/z80/src/z80/z80_registerdump.c
@@ -1,5 +1,5 @@
 /****************************************************************************
- * common/up_registerdump.c
+ * arch/z80/src/z80/z80_registerdump.c
  *
  *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
@@ -45,6 +45,7 @@
 #include <nuttx/irq.h>
 #include <nuttx/arch.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
@@ -70,11 +71,11 @@
  ****************************************************************************/
 
 /****************************************************************************
- * Name: up_registerdump
+ * Name: z80_registerdump
  ****************************************************************************/
 
 #ifdef CONFIG_ARCH_STACKDUMP
-static void up_registerdump(void)
+static void z80_registerdump(void)
 {
   if (current_regs)
     {
diff --git a/nuttx/arch/z80/src/z80/z80_restoreusercontext.asm b/nuttx/arch/z80/src/z80/z80_restoreusercontext.asm
index 5807fa811..27dbdf433 100644
--- a/nuttx/arch/z80/src/z80/z80_restoreusercontext.asm
+++ b/nuttx/arch/z80/src/z80/z80_restoreusercontext.asm
@@ -46,11 +46,11 @@
 	.globl	XCPT_PC		; Offset 8: Offset to PC at time of interrupt

 

 ;**************************************************************************

-; up_restoreusercontext

+; z80_restoreusercontext

 ;**************************************************************************

 

 	.area	_CODE

-_up_restoreusercontext:

+_z80_restoreusercontext:

 	; On entry, stack contains return address (not used), then address

 	; of the register save structure

 

diff --git a/nuttx/arch/z80/src/z80/z80_saveusercontext.asm b/nuttx/arch/z80/src/z80/z80_saveusercontext.asm
index 886872f37..807b3fce1 100644
--- a/nuttx/arch/z80/src/z80/z80_saveusercontext.asm
+++ b/nuttx/arch/z80/src/z80/z80_saveusercontext.asm
@@ -59,11 +59,11 @@
 	SP_OFFSET	==  6
 
 ;*************************************************************************
-; Name: up_saveusercontext
+; Name: z80_saveusercontext
 ;*************************************************************************
 
 	.area	_CODE
-_up_saveusercontext:
+_z80_saveusercontext:
 	; Set up a stack frame
 
 	push	ix			; Save IX and IY
diff --git a/nuttx/configs/z80sim/src/z80_decodeirq.c b/nuttx/arch/z80/src/z80/z80_sigsetup.c
index 0b52bc7a6..351745cd7 100644
--- a/nuttx/configs/z80sim/src/z80_decodeirq.c
+++ b/nuttx/arch/z80/src/z80/z80_sigsetup.c
@@ -1,7 +1,7 @@
-/********************************************************************************
- * board/z80_decodeirq.c
+/****************************************************************************
+ * arch/z80/src/z80/z80_sigsetup.c
  *
- *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -31,74 +31,57 @@
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  *
- ********************************************************************************/
+ ****************************************************************************/
 
-/********************************************************************************
+/****************************************************************************
  * Included Files
- ********************************************************************************/
+ ****************************************************************************/
 
 #include <nuttx/config.h>
 
 #include <sys/types.h>
-#include <nuttx/irq.h>
-#include <nuttx/arch.h>
-#include <assert.h>
-#include <debug.h>
+#include <arch/irq.h>
 
+#include "chip/switch.h"
 #include "os_internal.h"
 #include "up_internal.h"
 
-/********************************************************************************
+/****************************************************************************
  * Definitions
- ********************************************************************************/
+ ****************************************************************************/
 
-/********************************************************************************
- * Public Data
- ********************************************************************************/
-
-/********************************************************************************
+/****************************************************************************
  * Private Data
- ********************************************************************************/
+ ****************************************************************************/
 
-/********************************************************************************
+/****************************************************************************
  * Private Functions
- ********************************************************************************/
+ ****************************************************************************/
 
-/********************************************************************************
+/****************************************************************************
  * Public Functions
- ********************************************************************************/
-
-FAR chipreg_t *up_decodeirq(uint8 rstno, FAR chipreg_t *regs)
-{
-#ifdef CONFIG_SUPPRESS_INTERRUPTS
+ ****************************************************************************/
 
-  lib_lowprintf("Unexpected IRQ\n");
-  current_regs = regs;
-  PANIC(OSERR_ERREXCEPTION);
-  return NULL; /* Won't get here */
+/****************************************************************************
+ * Name: z80_copystate
+ ****************************************************************************/
 
-#else
-
-  /* Current regs non-zero indicates that we are processing an interrupt;
-   * current_regs is also used to manage interrupt level context switches.
+void z80_sigsetup(FAR _TCB *tcb, sig_deliver_t sigdeliver, FAR chipreg_t *regs)
+{
+  /* Save the return address and interrupt state. These will be restored by
+   * the signal trampoline after the signals have been delivered (via
+   * SIGNAL_RETURN).
    */
 
-  current_regs = regs;
+  tcb->xcp.sigdeliver    = sigdeliver;
+  tcb->xcp.saved_pc      = regs[XCPT_PC];
+  tcb->xcp.saved_i       = regs[XCPT_I];
 
-  /* Deliver the IRQ -- the simulation supports only timer interrupts and
-   * the IRQ maps to the reset number (real hardware probably needs an
-   * additional level of interrupt decoding.
-   */
-
-  irq_dispatch((int)rstno, regs);
+  /* Then set up to vector to the trampoline with interrupts disabled */
 
-  /* If a context switch occurred, current_regs will hold the new context */
+  regs[XCPT_PC]  = (uint16)up_sigdeliver;
+  regs[XCPT_I]   = 0;
+}
 
-  regs = current_regs;
 
-  /* Indicate that we are no long in an interrupt handler */
 
-  current_regs = NULL;
-  return regs;
-#endif
-}
diff --git a/nuttx/configs/z80sim/src/Makefile b/nuttx/configs/z80sim/src/Makefile
index be685f18c..46767d139 100644
--- a/nuttx/configs/z80sim/src/Makefile
+++ b/nuttx/configs/z80sim/src/Makefile
@@ -39,7 +39,7 @@ CFLAGS		+= -I$(TOPDIR)/sched -I$(TOPDIR)/arch/z80/src/common -I$(TOPDIR)/arch/z8
 
 ASRCS		= 
 AOBJS		= $(ASRCS:$(ASMEXT)=$(OBJEXT))
-CSRCS		= z80_decodeirq.c z80_irq.c z80_serial.c z80_timerisr.c z80_lowputc.c
+CSRCS		= z80_irq.c z80_serial.c z80_timerisr.c z80_lowputc.c
 COBJS		= $(CSRCS:.c=$(OBJEXT))
 
 SRCS		= $(ASRCS) $(CSRCS)
diff --git a/nuttx/configs/z80sim/src/z80_irq.c b/nuttx/configs/z80sim/src/z80_irq.c
index 5fd150359..c2b64a1d5 100644
--- a/nuttx/configs/z80sim/src/z80_irq.c
+++ b/nuttx/configs/z80sim/src/z80_irq.c
@@ -72,10 +72,6 @@
 
 void up_irqinitialize(void)
 {
-  /* currents_regs is non-NULL only while processing an interrupt */
-
-  current_regs = NULL;
-
   /* Attach the timer interrupt -- There is not special timer interrupt
    * enable in the simulation so it must be enabled here before interrupts
    * are enabled.