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/****************************************************************************
* arch/mips/src/mips32/up_syscall0.S
*
* Copyright (C) 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <arch/mips32/registers.h>
#include <arch/mips32/cp0.h>
/****************************************************************************
* Global Symbols
****************************************************************************/
.file "up_syscall0.S"
.global sys_call0
.global sys_call1
.global sys_call2
.global sys_call3
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_syscall0, up_syscall1, up_syscall2, up_syscall3
*
* Description:
* up_syscall0 - System call SYS_ argument and no additional parameters.
* up_syscall1 - System call SYS_ argument and one additional parameter.
* up_syscall2 - System call SYS_ argument and two additional parameters.
* up_syscall3 - System call SYS_ argument and three additional parameters.
*
* Assumption:
* All interrupts are disabled except for the software interrupts.
*
****************************************************************************/
.text
.set noreorder
.ent sys_call0
sys_call0: /* r4 holds the syscall number */
sys_call1: /* r4 holds the syscall number, argument in r5 */
sys_call2: /* r4 holds the syscall number, arguments in r5 and r6 */
sys_call3: /* r4 holds the syscall number, arguments in r5, r6, and r7 */
.set push
.set noat
/* Set Bit 8 to request the software interrupt */
mfc0 t3, MIPS32_CP0_CAUSE /* t3 = CP0 cause register */
ori t3, (1 << 8) /* Bit 8: Request software interrupt 0 */
.set noreorder
mtc0 t3, MIPS32_CP0_CAUSE /* Trigger the software interrupt */
/* The actual interrupt will not a occur for a few more cycles. Let's
* put a few nop's here in hope that the SW interrupt occurs during
* the sequence of nops.
*/
nop
nop
nop
nop
/* Then return with the result of the software interrupt in v0 */
j ra
nop
.end sys_call0
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