ref: 83ac1d52c8e021bcf4674787f621f736813dae4e
dir: /test/hello/syscall.s/
.globl sys$syscall
sys$syscall:
pushl %ebp
movl %esp,%ebp
movl 12(%ebp),%eax #count
shl $2,%eax
jmp *.jmptab(%eax)
.jmptab:
.long .a0
.long .a1
.long .a2
.long .a3
.long .a4
.long .a5
.long .a6
/*
hack: 6 args uses %ebp, so we index
relative to %esp. This means that if
we actually start using stack space,
this code will need adjustment
*/
.a6: movl 36(%esp),%ebp
.a5: movl 32(%esp),%edi
.a4: movl 28(%esp),%esi
.a3: movl 24(%esp),%edx
.a2: movl 20(%esp),%ecx
.a1: movl 16(%esp),%ebx
/* 12(%esp) holds nargs */
.a0: movl 8(%esp),%eax
int $0x80
movl %ebp,%esp
popl %ebp
ret