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LibC: Implement setjmp() and longjmp().

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I think this is correct. The following registers are saved and restored:
EBX, ESI, EDI, EBP, ESP and EIP.
This commit is contained in:
Andreas Kling 2019-01-26 06:23:16 +01:00
parent f34c0e414b
commit 57fb027216
1 changed files with 28 additions and 9 deletions
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37
LibC/setjmp.cpp
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@ -2,13 +2,32 @@
#include <assert.h> #include <assert.h>
#include <Kernel/Syscall.h> #include <Kernel/Syscall.h>
int setjmp(jmp_buf) asm(
{ "setjmp:\n\
//assert(false); movl %ebx, 0(%eax)\n\
return 0; movl %esi, 4(%eax)\n\
} movl %edi, 8(%eax)\n\
movl %ebp, 12(%eax)\n\
movl %esp, 16(%eax)\n\
movl (%esp), %ecx\n\
movl %ecx, 20(%eax)\n\
xorl %eax, %eax\n\
ret\n\
");
void longjmp(jmp_buf, int) asm(
{ "longjmp:\n\
assert(false); xchgl %edx, %eax\n\
} test %eax, %eax\n\
jnz 1f\n\
incl %eax\n\
1:\n\
mov 0(%edx), %ebx\n\
mov 4(%edx), %esi\n\
mov 8(%edx), %edi\n\
mov 12(%edx), %ebp\n\
mov 16(%edx), %ecx\n\
mov %ecx, %esp\n\
mov 20(%edx), %ecx\n\
jmp *%ecx\n\
");