136 lines
1.9 KiB
NASM
136 lines
1.9 KiB
NASM
extern NR_write
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extern strlen
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extern strcat
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section .rodata
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NL db 0xA
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section .bss
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printfBuff resb 4096
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section .text
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global print
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global puts
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global printf
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;----- print (char* string) -----;
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; return value: N/A
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print:
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push rbp
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mov rbp, rsp
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call strlen
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mov rdx, rax
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mov rax, NR_write
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mov rsi, rdi
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mov rdi, 1
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syscall
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leave
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ret
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;----- puts (char* string) -----;
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; return value: N/A
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puts:
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push rbp
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mov rbp, rsp
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mov r10, rdi
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call print
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mov rdi, r10
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mov rax, NR_write
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mov rdi, 1
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mov rsi, NL
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mov rdx, 1
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syscall
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leave
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ret
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;----- printf(const char* string, ...) -----;
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printf:
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push rbp
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mov rbp, rsp
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push r12
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push r13
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;sub rsp, 8
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xor r10, r10
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lea r11, [rel printfBuff]
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.makeStr:
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cmp byte [rdi], 0x0
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je .finish
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cmp byte [rdi], '%'
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je .replaceArg
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mov r12b, byte [rdi]
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mov byte [r11], r12b
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jmp .continue
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.replaceArg:
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cmp byte [rdi+1], 0x0
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je .continue
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cmp byte [rdi+1], 'd'
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je .rep_d
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cmp byte [rdi+1], 's'
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je .rep_s
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.rep_d:
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;TODO
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jmp .continue
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.rep_s:
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push rdi
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;mov byte [r11], 's' ;%s => Ss
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cmp r10, 0
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je .sinsertLoop ;nothing to do, rsi already correct
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cmp r10, 1
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je .rep_s_rdx
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cmp r10, 2
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je .rep_s_rcx
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cmp r10, 3
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je .rep_s_r8
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cmp r10, 4
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je .rep_s_r9
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;get from stack
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; rsp + 6*8 : RIP to printf call (+1), PUSH rbp,r12,r13,rdi (+4), +1 should be tS6
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mov rsi, qword [rsp + 5*8 + (r10-5)*8]
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jmp .sinsertLoop
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.rep_s_rdx:
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mov rsi, rdx
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jmp .sinsertLoop
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.rep_s_rcx:
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mov rsi, rcx
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jmp .sinsertLoop
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.rep_s_r8:
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mov rsi, r8
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jmp .sinsertLoop
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.rep_s_r9:
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mov rsi, r9
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.sinsertLoop:
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cmp byte [rsi], 0x0
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je .s0f
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mov r13b, byte [rsi]
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mov byte [r11], r13b
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inc rsi
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inc r11
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jmp .sinsertLoop
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.s0f:
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inc r10
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pop rdi
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add rdi, 2
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jmp .makeStr
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.continue:
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inc rdi
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inc r11
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jmp .makeStr
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.finish:
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mov byte [r11], 0x0
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lea rdi, [rel printfBuff]
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call print
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;add rsp, 8
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pop r13
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pop r12
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leave
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ret
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