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# Copyright (c) 2020 Johannes Stoelp
# SysV AMD64 ABI
# int/ptr args : rdi, rsi, rdx, rcx, r8, r9
# int/ptr ret : rax
.intel_syntax noprefix
.section .text, "ax", @progbits
# extern "C" void thread_create();
.global thread_create
.type thread_create, @function
thread_create:
.cfi_startproc
mov rdi, qword ptr [rsp+0x8]
mov rsi, qword ptr [rsp]
call rsi
# FIXME: no return from thread after user fn finished.
1:
jmp 1b
.cfi_endproc
.size thread_create, .-thread_create
# extern "C" void yield(const void* new_stack, void* const* old_stack);
# ^^^^^^^^^ ^^^^^^^^^
# rdi rsi
.global yield
.type yield, @function
yield:
.cfi_startproc
// prologue
push rbp
mov rbp, rsp
// push callee saved registers
push rbx
push rbp
push r12
push r13
push r14
push r15
// arg0: rdi holds new stack
// arg1: rsi holds addr to location current stack must be saved
mov [rsi], rsp # save current stack ptr
mov rsp, rdi # switch to new stack ptr
// pop callee saved registers
pop r15
pop r14
pop r13
pop r12
pop rbp
pop rbx
// epilogue
mov rsp, rbp
pop rbp
ret
.cfi_endproc
.size yield, .-yield
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