diff options
Diffstat (limited to 'nuttx/arch/x86/src/qemu/qemu_saveusercontext.S')
| -rw-r--r-- | nuttx/arch/x86/src/qemu/qemu_saveusercontext.S | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/nuttx/arch/x86/src/qemu/qemu_saveusercontext.S b/nuttx/arch/x86/src/qemu/qemu_saveusercontext.S index e9a98b331..427c3bd5d 100644 --- a/nuttx/arch/x86/src/qemu/qemu_saveusercontext.S +++ b/nuttx/arch/x86/src/qemu/qemu_saveusercontext.S @@ -126,11 +126,26 @@ up_saveusercontext: mov %cs, (4*REG_CS)(%eax) mov %ds, (4*REG_DS)(%eax) - /* Save the value of SP as will be after we return (don't bother to save - * REG_ESP). + /* Save the value of SP as will be at the time of the IRET that will + * appear to be the return from this function. + * + * + * CURRENT STACK IRET STACK + * PRIO CHANGE No PRIO CHANGE + * --------------- --------------- ----------------- + * EIP + * CS ... + * EFLAGS EIP + * -> ESP CS + * ESP->Return address SS EFLAGS + * Argument Argument Argument + * + * NOTE: We don't yet know the value for REG_ESP! That depends upon + * if a priority change occurs or not. */ - leal 4(%esp), %ecx + + leal -4(%esp), %ecx movl %ecx, (4*REG_SP)(%eax) /* Fetch the PC from the stack and save it in the save block */ |