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temoto/taskswitch.s

Created September 18, 2010 21:58
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taskswitch.s
; Copied from http://newos.org/txt/context_switch.txt
BITS 32
global HalSwitchContext
section .text
; void i386_context_switch(void **from_esp, void *esp)
HalSwitchContext:
pusha ; save all 8 general purpose regs on the stack
lea eax, [esp+36]
mov [eax], esp ; save the current esp -> *from_esp
mov eax, [esp+40]
mov esp, eax ; load esp from -> *esp
popa ; restore all 8 general purpose regs from the new stack
ret ; return to caller: usually the bottom part of reschedule()
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temoto commented Sep 18, 2010

nasm -g -f elf32 -o arch/i386/hal/taskswitch.o arch/i386/hal/taskswitch.s
arch/i386/hal/taskswitch.s:13: error: expression syntax error

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