liblinux++

A hosted C++ runtime without any libc.
git clone git://henryandlizzy.uk/liblinux++
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x86_64.S (682B)

      1 #include "NR_x86_64.h"
      2 
      3 .intel_syntax noprefix
      4 
      5 .global start
      6 
      7 .text
      8 
      9 start:	# start is the entry point known to the linker
     10 	mov	edi,	[rsp]		# get argc from the stack
     11 	lea	rsi,	[rsp+8]		# take the address of argv from the stack
     12 	lea	rdx,	[rsp+16]	# take the address of envp from the stack
     13 	call	main			# %edi, %rsi, %rdx are the three args (of which first two are C standard) to main
     14 	mov	rdi,	rax
     15 	jmp exit
     16 
     17 .macro extern_alias, name
     18 .global \name
     19 \name:
     20 .endm
     21 
     22 .macro extern, name
     23 .section .text.\name
     24 extern_alias \name
     25 .endm
     26 
     27 .macro _syscall, num, impl
     28 	mov	rax,	\num
     29 	push	r11
     30 	mov	r10,	rcx
     31 	syscall
     32 	pop	r11
     33 	ret
     34 .endm
     35 
     36 #define SYS(x) _syscall __NR_##x
     37 
     38 #include "syscalls.h"