/
md_cygwin64.S
79 lines (67 loc) · 3.92 KB
/
md_cygwin64.S
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/* SPDX-License-Identifier: MIT */
/* Copyright (c) 2021-2022 The SRS Authors */
/* If user disable the ASM, such as avoiding bugs in ASM, donot compile it. */
#if !defined(MD_ST_NO_ASM)
#if defined(__amd64__) || defined(__x86_64__)
/****************************************************************/
/*
* Internal __jmp_buf layout
*/
#define JB_RBX 0
#define JB_RBP 1
#define JB_R12 2 /* R12:R15 Nonvolatile Must be preserved by callee */
#define JB_R13 3 /* @see https://docs.microsoft.com/en-us/cpp/build/x64-software-conventions?view=msvc-160#register-usage */
#define JB_R14 4 /* RBX, RBP, RDI, RSI, R12, R14, R14, and R15 must be saved in any function using them. */
#define JB_R15 5 /* @see https://software.intel.com/content/www/us/en/develop/articles/introduction-to-x64-assembly.html */
#define JB_RSP 6
#define JB_PC 7
.file "md_cygwin64.S"
.text
/* _st_md_cxt_save(__jmp_buf env) */ /* The env is rcx, https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-160 */
.globl _st_md_cxt_save
.align 16
_st_md_cxt_save:
/*
* Save registers.
*/
movq %rbx, (JB_RBX*8)(%rcx) /* Save rbx to env[0], *(int64_t*)(rcx+0)=rbx */
movq %rbp, (JB_RBP*8)(%rcx) /* Save rbp to env[1], *(int64_t*)(rcx+1)=rbp */
movq %r12, (JB_R12*8)(%rcx) /* Save r12 to env[2], *(int64_t*)(rcx+2)=r12 */
movq %r13, (JB_R13*8)(%rcx) /* Save r13 to env[3], *(int64_t*)(rcx+3)=r13 */
movq %r14, (JB_R14*8)(%rcx) /* Save r14 to env[4], *(int64_t*)(rcx+4)=r14 */
movq %r15, (JB_R15*8)(%rcx) /* Save r15 to env[5], *(int64_t*)(rcx+5)=r15 */
/* Save SP */
leaq 8(%rsp), %r8 /* Save *(int64_t*)(rsp+8) to r8, https://github.com/ossrs/state-threads/issues/20#issuecomment-887569093 */
movq %r8, (JB_RSP*8)(%rcx) /* Save r8(rsp) to env[6], *(int64_t*)(rcx+6)=r8 */
/* Save PC we are returning to */
movq (%rsp), %r9 /* Save PC(parent function address) %(rsp) to r9, https://github.com/ossrs/state-threads/issues/20#issuecomment-887569093 */
movq %r9, (JB_PC*8)(%rcx) /* Save r9(PC) to env[7], *(int64_t*)(rcx+7)=r9 */
xorq %rax, %rax /* Reset rax(return value) to 0 */
ret
/****************************************************************/
/* _st_md_cxt_restore(__jmp_buf env, int val) */ /* The env is rcx, val is edx/rdx, https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-160 */
.globl _st_md_cxt_restore
.align 16
_st_md_cxt_restore:
/*
* Restore registers.
*/
movq (JB_RBX*8)(%rcx), %rbx /* Load rbx from env[0] */
movq (JB_RBP*8)(%rcx), %rbp /* Load rbp from env[1] */
movq (JB_R12*8)(%rcx), %r12 /* Load r12 from env[2] */
movq (JB_R13*8)(%rcx), %r13 /* Load r13 from env[3] */
movq (JB_R14*8)(%rcx), %r14 /* Load r14 from env[4] */
movq (JB_R15*8)(%rcx), %r15 /* Load r15 from env[5] */
/* Set return value */ /* The edx is param1 val, the eax is return value */
test %edx, %edx /* if (!val) { */
mov $01, %eax /* val=1; */
cmove %eax, %edx /* } */
mov %edx, %eax /* return val; */
/* Restore PC and RSP */
movq (JB_PC*8)(%rcx), %r8 /* Load r8(PC) from env[7], https://github.com/ossrs/state-threads/issues/20#issuecomment-887569093 */
movq (JB_RSP*8)(%rcx), %rsp /* Load rsp from env[6] */
/* Jump to saved PC */
jmpq *%r8 /* Jump to r8(PC) */
/****************************************************************/
#endif
#endif