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|
.include "lib.s"
.macro bufpush
cmpq $bufend, %rdi
jle 9f
stosb
9:
.endm
.globl printf
printf:
prologue
backup %rax, %rbx, %rcx, %rdx
backup %rsi, %rdi
movq 16(%rbp), %rsi
leaq 24(%rbp), %rbx
movq $buf, %rdi
.loop:
lodsb
testb %al, %al
jz .loopout
cmpb $'%, %al
jne .append
lodsb
testb %al, %al
jz .loopout
cmpb $'%, %al
je .append
cmpb $'s, %al
je .print_string
cmpb $'d, %al
je .print_signed
cmpb $'u, %al
je .print_unsigned
jmp .loop
.append:
bufpush
jmp .loop
.print_string:
backup %rsi
movq (%rbx), %rsi
addq $8, %rbx
jmp 2f
1: bufpush
2: lodsb
testb %al, %al
jnz 1b
restore %rsi
jmp .loop
.print_signed:
movq (%rbx), %rax
addq $8, %rbx
cmpq $0, %rax
jge 1f
pushq %rax
movb $'-, %al
bufpush
popq %rax
negq %rax
1:
movq $10, %rcx
call .print_number
jmp .loop
.print_unsigned:
movq (%rbx), %rax
addq $8, %rbx
movq $10, %rcx
call .print_number
jmp .loop
.print_number:
xorq %rdx, %rdx
divq %rcx
pushq %rdx
testq %rax, %rax
jz 1f
call .print_number
1:
popq %rax
addq $'0, %rax
bufpush
ret
.loopout:
movq %rdi, %rdx
subq $buf, %rdx
movq $buf, %rsi
movq $STDOUT, %rdi
sys write
restore %rsi, %rdi
restore %rax, %rbx, %rcx, %rdx
leave
ret
.bss
.comm buf, 4096
.comm bufend, 2
|
