239 lines
3.7 KiB
NASM
239 lines
3.7 KiB
NASM
extern NR_write
|
|
extern strlen
|
|
extern strcat
|
|
extern itoa
|
|
|
|
section .rodata
|
|
NL db 0xA
|
|
section .bss
|
|
printfBuff resb 4096
|
|
printfNBuff resb 32
|
|
section .text
|
|
global print
|
|
global puts
|
|
global printf
|
|
|
|
;----- print (char* string) -----;
|
|
; return value: N/A
|
|
print:
|
|
push rbp
|
|
mov rbp, rsp
|
|
|
|
call strlen
|
|
mov rdx, rax
|
|
mov rax, NR_write
|
|
mov rsi, rdi
|
|
mov rdi, 1
|
|
syscall
|
|
|
|
leave
|
|
ret
|
|
;----- puts (char* string) -----;
|
|
; return value: N/A
|
|
puts:
|
|
push rbp
|
|
mov rbp, rsp
|
|
|
|
mov r10, rdi
|
|
call print
|
|
mov rdi, r10
|
|
mov rax, NR_write
|
|
mov rdi, 1
|
|
mov rsi, NL
|
|
mov rdx, 1
|
|
syscall
|
|
|
|
leave
|
|
ret
|
|
;----- printf(const char* string, ...) -----;
|
|
; Currently only supports specifiers: %d, %c, %s, %%
|
|
; Return value: Amount of printed characters
|
|
printf:
|
|
push rbp
|
|
mov rbp, rsp
|
|
|
|
push r12
|
|
push r13
|
|
|
|
xor r10, r10
|
|
lea r11, [rel printfBuff]
|
|
.makeStr:
|
|
cmp byte [rdi], 0x0
|
|
je .finish
|
|
cmp byte [rdi], '%'
|
|
je .replaceArg
|
|
mov r12b, byte [rdi]
|
|
mov byte [r11], r12b
|
|
jmp .continue
|
|
.replaceArg:
|
|
cmp byte [rdi+1], 0x0
|
|
je .continue
|
|
push rdi
|
|
cmp byte [rdi+1], 'd'
|
|
je .rep_d
|
|
cmp byte [rdi+1], '%'
|
|
je .rep_pct
|
|
cmp byte [rdi+1], 'c'
|
|
je .rep_c
|
|
cmp byte [rdi+1], 's'
|
|
je .rep_s
|
|
|
|
;--- invalid specifier ---;
|
|
mov byte [r11], '%'
|
|
inc r10 ;assuming args were passed for invalid specifiers !
|
|
jmp .continue
|
|
|
|
;--- %d ---;
|
|
.rep_d:
|
|
cmp r10, 0
|
|
je .rep_d_rsi
|
|
cmp r10, 1
|
|
je .rep_d_rdx
|
|
cmp r10, 2
|
|
je .rep_d_rcx
|
|
cmp r10, 3
|
|
je .rep_d_r8
|
|
cmp r10, 4
|
|
je .rep_d_r9
|
|
|
|
;get from stack
|
|
mov rdi, qword [rbp + 16 + (r10-5)*8]
|
|
jmp .convertInt
|
|
|
|
.rep_d_rsi:
|
|
mov rdi, rsi
|
|
jmp .convertInt
|
|
.rep_d_rdx:
|
|
mov rdi, rdx
|
|
jmp .convertInt
|
|
.rep_d_rcx:
|
|
mov rdi, rcx
|
|
jmp .convertInt
|
|
.rep_d_r8:
|
|
mov rdi, r8
|
|
jmp .convertInt
|
|
.rep_d_r9:
|
|
mov rdi, r9
|
|
|
|
.convertInt:
|
|
lea rsi, [rel printfNBuff]
|
|
push rcx
|
|
push rdx
|
|
push r8
|
|
push r10
|
|
push rsi
|
|
call itoa
|
|
pop rsi
|
|
pop r10
|
|
pop r8
|
|
pop rdx
|
|
pop rcx
|
|
mov rsi, rax
|
|
jmp .insertLoop
|
|
|
|
;--- %% ---;
|
|
.rep_pct:
|
|
mov rdi, '%'
|
|
dec r10 ;r10 is increased at the end, but not needed because '%%' requires no arg
|
|
jmp .charToStr
|
|
|
|
;--- %c ---;
|
|
.rep_c:
|
|
cmp r10, 0
|
|
je .rep_c_rsi
|
|
cmp r10, 1
|
|
je .rep_c_rdx
|
|
cmp r10, 2
|
|
je .rep_c_rcx
|
|
cmp r10, 3
|
|
je .rep_c_r8
|
|
cmp r10, 4
|
|
je .rep_c_r9
|
|
|
|
;get from stack
|
|
mov rdi, qword [rbp + 16 + (r10-5)*8]
|
|
jmp .charToStr
|
|
|
|
.rep_c_rsi:
|
|
mov rdi, rsi
|
|
jmp .charToStr
|
|
.rep_c_rdx:
|
|
mov rdi, rdx
|
|
jmp .charToStr
|
|
.rep_c_rcx:
|
|
mov rdi, rcx
|
|
jmp .charToStr
|
|
.rep_c_r8:
|
|
mov rdi, r8
|
|
jmp .charToStr
|
|
.rep_c_r9:
|
|
mov rdi, r9
|
|
jmp .charToStr
|
|
|
|
.charToStr:
|
|
mov [printfNBuff], dil
|
|
mov dil, 0
|
|
mov [printfNBuff+1], dil
|
|
lea rsi, [rel printfNBuff]
|
|
jmp .insertLoop
|
|
|
|
;--- %s ---;
|
|
.rep_s:
|
|
cmp r10, 0
|
|
je .insertLoop ;nothing to do, rsi already correct
|
|
cmp r10, 1
|
|
je .rep_s_rdx
|
|
cmp r10, 2
|
|
je .rep_s_rcx
|
|
cmp r10, 3
|
|
je .rep_s_r8
|
|
cmp r10, 4
|
|
je .rep_s_r9
|
|
|
|
;get from stack
|
|
mov rsi, qword [rbp + 16 + (r10-5)*8]
|
|
jmp .insertLoop
|
|
|
|
.rep_s_rdx:
|
|
mov rsi, rdx
|
|
jmp .insertLoop
|
|
.rep_s_rcx:
|
|
mov rsi, rcx
|
|
jmp .insertLoop
|
|
.rep_s_r8:
|
|
mov rsi, r8
|
|
jmp .insertLoop
|
|
.rep_s_r9:
|
|
mov rsi, r9
|
|
|
|
;--- Move fetched data to buffer ---;
|
|
.insertLoop:
|
|
cmp byte [rsi], 0x0
|
|
je .s0f
|
|
mov r13b, byte [rsi]
|
|
mov byte [r11], r13b
|
|
inc rsi
|
|
inc r11
|
|
jmp .insertLoop
|
|
.s0f:
|
|
inc r10
|
|
pop rdi
|
|
add rdi, 2
|
|
jmp .makeStr
|
|
.continue:
|
|
inc rdi
|
|
inc r11
|
|
jmp .makeStr
|
|
.finish:
|
|
mov byte [r11], 0x0
|
|
lea rdi, [rel printfBuff]
|
|
call print
|
|
lea rdi, [rel printfBuff]
|
|
call strlen
|
|
|
|
pop r13
|
|
pop r12
|
|
|
|
leave
|
|
ret
|