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.text
.globl aco_yield_asm
#if defined(__APPLE__)
#else
.type aco_yield_asm, @function
#endif
.intel_syntax noprefix
aco_yield_asm:
/*
extern void aco_yield_asm(aco_t* from_co, aco_t* to_co);
struct aco_t {
void* reg[X];
// ...
}
reference:
https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI
pitfall:
http://man7.org/linux/man-pages/man7/signal.7.html
http://man7.org/linux/man-pages/man2/sigaltstack.2.html
> $ man 7 signal
> ...
> By default, the signal handler is invoked on the normal process
> stack. It is possible to arrange that the signal handler
> uses an alternate stack; see sigaltstack(2) for a discussion of
> how to do this and when it might be useful.
> ...
This is a BUG example:
https://github.com/Tencent/libco/blob/v1.0/coctx_swap.S#L27
proof of correctness:
https://github.com/hnes/libaco
mxcsr & fpu:
fnstcw * m2byte
Store FPU control word to m2byte without checking for
pending unmasked floating-point exceptions.
fldcw m2byte
Load FPU control word from m2byte.
stmxcsr m32
Store contents of MXCSR register to m32
ldmxcsr m32
Load MXCSR register from m32.
*/
/*
0x00 --> 0xff
eip esp ebp edi esi ebx fpucw16 mxcsr32
0 4 8 c 10 14 18 1c
*/
#ifdef __i386__
mov eax,DWORD PTR [esp+0x4] // from_co
mov edx,DWORD PTR [esp] // retaddr
lea ecx,[esp+0x4] // esp
mov DWORD PTR [eax+0x8],ebp //<ebp
mov DWORD PTR [eax+0x4],ecx //<esp
mov DWORD PTR [eax+0x0],edx //<retaddr
mov DWORD PTR [eax+0xc],edi //<edi
mov ecx,DWORD PTR [esp+0x8] // to_co
mov DWORD PTR [eax+0x10],esi //<esi
mov DWORD PTR [eax+0x14],ebx //<ebx
#ifndef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
fnstcw WORD PTR [eax+0x18] //<fpucw
stmxcsr DWORD PTR [eax+0x1c] //<mxcsr
#endif
mov edx,DWORD PTR [ecx+0x4] //>esp
mov ebp,DWORD PTR [ecx+0x8] //>ebp
mov eax,DWORD PTR [ecx+0x0] //>retaddr
mov edi,DWORD PTR [ecx+0xc] //>edi
mov esi,DWORD PTR [ecx+0x10] //>esi
mov ebx,DWORD PTR [ecx+0x14] //>ebx
#ifndef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
fldcw WORD PTR [ecx+0x18] //>fpucw
ldmxcsr DWORD PTR [ecx+0x1c] //>mxcsr
#endif
xor ecx,ecx
mov esp,edx
mov edx,eax
// Pass the user-provided argument as first argument:
#ifdef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
mov eax,DWORD PTR [ecx+0x24]
#else
mov eax,DWORD PTR [ecx+0x28]
#endif
jmp edx
#elif __x86_64__
/*
0x00 --> 0xff
r12 r13 r14 r15 rip rsp rbx rbp fpucw16 mxcsr32
0 8 10 18 20 28 30 38 40 44
*/
// rdi - from_co | rsi - to_co
mov rdx,QWORD PTR [rsp] // retaddr
lea rcx,[rsp+0x8] // rsp
mov QWORD PTR [rdi+0x0], r12
mov QWORD PTR [rdi+0x8], r13
mov QWORD PTR [rdi+0x10],r14
mov QWORD PTR [rdi+0x18],r15
mov QWORD PTR [rdi+0x20],rdx // retaddr
mov QWORD PTR [rdi+0x28],rcx // rsp
mov QWORD PTR [rdi+0x30],rbx
mov QWORD PTR [rdi+0x38],rbp
#ifndef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
fnstcw WORD PTR [rdi+0x40]
stmxcsr DWORD PTR [rdi+0x44]
#endif
mov r12,QWORD PTR [rsi+0x0]
mov r13,QWORD PTR [rsi+0x8]
mov r14,QWORD PTR [rsi+0x10]
mov r15,QWORD PTR [rsi+0x18]
mov rax,QWORD PTR [rsi+0x20] // retaddr
mov rcx,QWORD PTR [rsi+0x28] // rsp
mov rbx,QWORD PTR [rsi+0x30]
mov rbp,QWORD PTR [rsi+0x38]
#ifndef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
fldcw WORD PTR [rsi+0x40]
ldmxcsr DWORD PTR [rsi+0x44]
#endif
// Pass the user-provided argument as first argument:
#ifdef ACO_CONFIG_SHARE_FPU_MXCSR_ENV
mov rdi,QWORD PTR [rsi+0x48]
#else
mov rdi,QWORD PTR [rsi+0x50]
#endif
mov rsp,rcx
jmp rax
#else
#error "platform not supported"
#endif
.globl aco_save_fpucw_mxcsr
#if defined(__APPLE__)
#else
.type aco_save_fpucw_mxcsr, @function
#endif
.intel_syntax noprefix
aco_save_fpucw_mxcsr:
#ifdef __i386__
mov eax,DWORD PTR [esp+0x4] // ptr
fnstcw WORD PTR [eax]
stmxcsr DWORD PTR [eax+0x4]
ret
#elif __x86_64__
fnstcw WORD PTR [rdi]
stmxcsr DWORD PTR [rdi+0x4]
ret
#else
#error "platform not supported"
#endif
#if defined(__APPLE__)
.globl _abort
.globl _aco_funcp_protector
#else
.globl abort
.globl aco_funcp_protector
#endif
.globl aco_funcp_protector_asm
#if defined(__APPLE__)
#else
.type aco_funcp_protector_asm, @function
#endif
.intel_syntax noprefix
aco_funcp_protector_asm:
#ifdef __i386__
and esp,0xfffffff0
#if defined(__APPLE__)
call _aco_funcp_protector
call _abort
#else
#if defined(__pic__) || defined(__PIC__)
call aco_funcp_protector@PLT
call abort@PLT
#else
call aco_funcp_protector
call abort
#endif
#endif
ret
#elif __x86_64__
and rsp,0xfffffffffffffff0
#if defined(__APPLE__)
call _aco_funcp_protector
call _abort
#else
#if defined(__pic__) || defined(__PIC__)
call aco_funcp_protector@PLT
call abort@PLT
#else
call aco_funcp_protector
call abort
#endif
#endif
ret
#else
#error "platform not supported"
#endif
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