614 lines
11 KiB
NASM
614 lines
11 KiB
NASM
section .text
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%define DSTK_BYTES 65536
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%define RSTK_BYTES 65536
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%define PRINT_BUF_BYTES 128
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global _start
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_start:
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; initialize data/return stack pointers
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lea r12, [rel dstack_top]
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mov r15, r12
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lea r13, [rel rstack_top]
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call word_main
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mov rax, 0
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cmp r12, r15
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je .no_exit_value
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mov rax, [r12]
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add r12, 8
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.no_exit_value:
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mov rdi, rax
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mov rax, 60
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syscall
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word_c_40:
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mov rax, [r12]
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movzx rax, byte [rax]
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mov [r12], rax
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ret
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ret
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word_c_21:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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mov [rbx], al
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ret
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ret
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word_r_40:
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mov rax, [r13]
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sub r12, 8
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mov [r12], rax
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ret
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ret
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word_puts:
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; detects string if top is len>=0 and next is a pointer in [data_start, data_end]
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mov rax, [r12] ; len or int value
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mov rbx, [r12 + 8] ; possible address
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cmp rax, 0
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jl puts_print_int
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lea r8, [rel data_start]
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lea r9, [rel data_end]
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cmp rbx, r8
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jl puts_print_int
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cmp rbx, r9
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jge puts_print_int
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; treat as string: (addr below len)
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mov rdx, rax ; len
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mov rsi, rbx ; addr
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add r12, 16 ; pop len + addr
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test rdx, rdx
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jz puts_str_newline_only
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mov rax, 1
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mov rdi, 1
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syscall
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puts_str_newline_only:
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mov byte [rel print_buf], 10
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mov rax, 1
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mov rdi, 1
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lea rsi, [rel print_buf]
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mov rdx, 1
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syscall
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ret
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puts_print_int:
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mov rax, [r12]
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add r12, 8
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mov rbx, rax
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mov r8, 0
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cmp rbx, 0
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jge puts_abs
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neg rbx
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mov r8, 1
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puts_abs:
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lea rsi, [rel print_buf_end]
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mov rcx, 0
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mov r10, 10
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cmp rbx, 0
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jne puts_digits
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dec rsi
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mov byte [rsi], '0'
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inc rcx
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jmp puts_sign
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puts_digits:
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puts_loop:
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xor rdx, rdx
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mov rax, rbx
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div r10
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add dl, '0'
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dec rsi
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mov [rsi], dl
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inc rcx
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mov rbx, rax
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test rbx, rbx
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jne puts_loop
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puts_sign:
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cmp r8, 0
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je puts_finish_digits
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dec rsi
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mov byte [rsi], '-'
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inc rcx
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puts_finish_digits:
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mov byte [rsi + rcx], 10
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inc rcx
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mov rax, 1
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mov rdi, 1
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mov rdx, rcx
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mov r9, rsi
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mov rsi, r9
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syscall
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ret
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word_dup:
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mov rax, [r12]
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sub r12, 8
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mov [r12], rax
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ret
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word_write_buf:
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mov rdx, [r12] ; len
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mov rsi, [r12 + 8] ; addr
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add r12, 16 ; pop len + addr
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mov rax, 1 ; syscall: write
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mov rdi, 1 ; fd = stdout
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syscall
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ret
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ret
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word_drop:
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add r12, 8
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ret
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word_over:
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mov rax, [r12 + 8]
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sub r12, 8
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mov [r12], rax
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ret
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word_swap:
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mov rax, [r12]
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mov rbx, [r12 + 8]
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mov [r12], rbx
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mov [r12 + 8], rax
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ret
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word_rot:
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mov rax, [r12] ; x3
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mov rbx, [r12 + 8] ; x2
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mov rcx, [r12 + 16] ; x1
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mov [r12], rcx ; top = x1
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mov [r12 + 8], rax ; next = x3
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mov [r12 + 16], rbx ; third = x2
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ret
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word__2drot:
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mov rax, [r12] ; x3
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mov rbx, [r12 + 8] ; x2
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mov rcx, [r12 + 16] ; x1
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mov [r12], rbx ; top = x2
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mov [r12 + 8], rcx ; next = x1
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mov [r12 + 16], rax ; third = x3
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ret
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word_nip:
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mov rax, [r12]
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add r12, 8 ; drop lower element
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mov [r12], rax ; keep original top
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ret
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word_tuck:
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mov rax, [r12] ; x2
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mov rbx, [r12 + 8] ; x1
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sub r12, 8 ; make room
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mov [r12], rax ; x2
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mov [r12 + 8], rbx ; x1
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mov [r12 + 16], rax ; x2
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ret
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word_2dup:
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mov rax, [r12] ; b
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mov rbx, [r12 + 8] ; a
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sub r12, 8
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mov [r12], rbx ; push a
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sub r12, 8
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mov [r12], rax ; push b
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ret
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word_2drop:
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add r12, 16
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ret
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word_2swap:
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mov rax, [r12] ; d
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mov rbx, [r12 + 8] ; c
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mov rcx, [r12 + 16] ; b
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mov rdx, [r12 + 24] ; a
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mov [r12], rcx ; top = b
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mov [r12 + 8], rdx ; next = a
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mov [r12 + 16], rax ; third = d
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mov [r12 + 24], rbx ; fourth = c
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ret
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word_2over:
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mov rax, [r12 + 16] ; b
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mov rbx, [r12 + 24] ; a
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sub r12, 8
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mov [r12], rbx ; push a
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sub r12, 8
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mov [r12], rax ; push b
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ret
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word__2b:
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mov rax, [r12]
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add r12, 8
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add qword [r12], rax
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ret
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word__2d:
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mov rax, [r12]
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add r12, 8
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sub qword [r12], rax
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ret
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word__2a:
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mov rax, [r12]
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add r12, 8
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imul qword [r12]
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mov [r12], rax
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ret
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word__2f:
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mov rbx, [r12]
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add r12, 8
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mov rax, [r12]
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cqo
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idiv rbx
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mov [r12], rax
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ret
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word__25:
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mov rbx, [r12]
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add r12, 8
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mov rax, [r12]
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cqo
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idiv rbx
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mov [r12], rdx
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ret
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word__3d_3d:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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sete bl
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mov [r12], rbx
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ret
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word__21_3d:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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setne bl
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mov [r12], rbx
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ret
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word__3c:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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setl bl
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mov [r12], rbx
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ret
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word__3e:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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setg bl
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mov [r12], rbx
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ret
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word__3c_3d:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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setle bl
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mov [r12], rbx
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ret
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word__3e_3d:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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cmp rbx, rax
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mov rbx, 0
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setge bl
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mov [r12], rbx
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ret
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word__40:
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mov rax, [r12]
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mov rax, [rax]
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mov [r12], rax
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ret
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word__21:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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mov [rax], rbx
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add r12, 8
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ret
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word_mmap:
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; Save rsp and align to 16 bytes for syscall ABI
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mov rax, rsp
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and rsp, -16
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mov rdi, [r12+40] ; addr
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mov rsi, [r12+32] ; length
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mov rdx, [r12+24] ; prot
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mov r10, [r12+16] ; flags
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mov r8, [r12+8] ; fd
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mov r9, [r12] ; offset
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add r12, 48 ; pop 6 args
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mov rax, 9 ; syscall: mmap
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syscall
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mov rsp, rax ; restore rsp
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sub r12, 8
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mov [r12], rax ; push result
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ret
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ret
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word_munmap:
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mov rsi, [r12]
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add r12, 8
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mov rdi, [r12]
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mov rax, 11
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syscall
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mov [r12], rax
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ret
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word_exit:
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mov rdi, [r12]
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add r12, 8
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mov rax, 60
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syscall
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ret
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word_and:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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test rax, rax
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setz cl
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test rbx, rbx
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setz dl
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movzx rcx, cl
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movzx rdx, dl
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and rcx, rdx
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mov [r12], rcx
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ret
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word_or:
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mov rax, [r12]
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add r12, 8
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mov rbx, [r12]
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test rax, rax
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setz cl
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test rbx, rbx
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setz dl
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movzx rcx, cl
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movzx rdx, dl
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or rcx, rdx
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mov [r12], rcx
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ret
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word_not:
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mov rax, [r12]
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test rax, rax
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setz al
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movzx rax, al
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mov [r12], rax
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ret
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word__3er:
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mov rax, [r12]
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add r12, 8
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sub r13, 8
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mov [r13], rax
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ret
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word_r_3e:
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mov rax, [r13]
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add r13, 8
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sub r12, 8
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mov [r12], rax
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ret
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word_rdrop:
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add r13, 8
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ret
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word_pick:
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mov rcx, [r12]
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add r12, 8
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mov rax, [r12 + rcx * 8]
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sub r12, 8
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mov [r12], rax
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ret
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word_rpick:
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mov rcx, [r12]
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add r12, 8
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mov rax, [r13 + rcx * 8]
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sub r12, 8
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mov [r12], rax
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ret
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word_read_file:
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; stack: path_ptr (top), path_len (next)
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mov rsi, [r12] ; path_ptr
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mov rdx, [r12 + 8] ; path_len
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add r12, 16 ; pop args
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; open(path_ptr, O_RDONLY=0, mode=0)
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mov rax, 2 ; syscall: open
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mov rdi, rsi ; filename
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xor rsi, rsi ; flags = O_RDONLY
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xor rdx, rdx ; mode = 0
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syscall
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mov r10, rax ; save open() result
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cmp rax, 0
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jl .fail_open
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mov r8, rax ; fd
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; use lseek to determine file size: lseek(fd, 0, SEEK_END)
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mov rax, 8 ; syscall: lseek
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mov rdi, r8 ; fd
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xor rsi, rsi ; offset = 0
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mov rdx, 2 ; SEEK_END
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syscall
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mov r11, rax ; save lseek() result
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cmp rax, 0
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jl .close_fail_lseek
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mov rsi, rax ; length = size
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; mmap(NULL, size, PROT_READ=1, MAP_PRIVATE=2, fd, 0)
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mov rax, 9 ; syscall: mmap
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xor rdi, rdi ; addr = NULL
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; rsi already holds length
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mov rdx, 1 ; PROT_READ
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mov r10, 2 ; MAP_PRIVATE
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mov r8, r8 ; fd
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xor r9, r9 ; offset = 0
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syscall
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mov rbx, rax ; addr
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mov r12, r12 ; (no-op, for debug)
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mov rax, 3 ; syscall: close
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mov rdi, r8 ; fd
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syscall
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cmp rbx, -4095
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jae .fail_mmap
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sub r12, 16
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mov [r12], rsi ; len (rsi held length across syscall)
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mov [r12 + 8], rbx ; addr
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ret
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.close_fail_lseek:
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mov rax, 3
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mov rdi, r8
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syscall
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mov rax, r11 ; return lseek() error code
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sub r12, 16
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mov [r12], rax
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mov qword [r12 + 8], -1
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ret
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.fail_open:
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mov rax, r10 ; return open() error code
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sub r12, 16
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mov [r12], rax
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mov qword [r12 + 8], -2
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ret
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.fail_mmap:
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mov rax, -1 ; return mmap() error
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sub r12, 16
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mov [r12], rax
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mov qword [r12 + 8], -3
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ret
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ret
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word_write_file:
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; stack: path_ptr (top), path_len, buf_ptr, buf_len
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mov rsi, [r12] ; path_ptr
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mov rdx, [r12 + 8] ; path_len
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mov r15, [r12 + 16] ; buf_ptr (save in callee-saved r15)
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mov r13, [r12 + 24] ; buf_len (save in callee-saved r13)
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add r12, 32 ; pop 4 args (we saved buf info)
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; open(path_ptr, O_WRONLY|O_CREAT|O_TRUNC, 0666)
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mov rdi, rsi ; filename
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mov rsi, 577 ; flags = O_WRONLY|O_CREAT|O_TRUNC
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mov rdx, 438 ; mode = 0o666
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mov rax, 2 ; syscall: open
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syscall
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cmp rax, 0
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jl .fail_open
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mov r9, rax ; save fd
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; write(fd, buf_ptr, buf_len) -- use preserved r15/r13 which survive syscalls
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mov rax, 1 ; syscall: write
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mov rdi, r9 ; fd
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mov rsi, r15 ; buf_ptr
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mov rdx, r13 ; buf_len
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syscall
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mov r10, rax ; save write result
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cmp r10, 0
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jl .fail_write
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; close(fd)
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mov rax, 3 ; syscall: close
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mov rdi, r9
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syscall
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sub r12, 8
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mov [r12], r10
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ret
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.fail_write:
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mov rax, 3
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mov rdi, r9
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syscall
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sub r12, 8
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mov [r12], r10
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ret
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.fail_open:
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sub r12, 8
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mov [r12], rax
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ret
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ret
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word_read_stdin:
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; stack: max_len
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mov r14, [r12] ; max_len
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add r12, 8 ; pop max_len
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; mmap(NULL, max_len, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0)
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mov rax, 9 ; syscall: mmap
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xor rdi, rdi ; addr = NULL
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mov rsi, r14 ; length
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mov rdx, 3 ; PROT_READ|PROT_WRITE
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mov r10, 34 ; MAP_PRIVATE|MAP_ANONYMOUS
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mov r8, -1 ; fd = -1
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xor r9, r9 ; offset = 0
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syscall
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cmp rax, -4095
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jae .fail_mmap
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mov rbx, rax ; buffer addr
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xor rcx, rcx ; bytes_read = 0
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.read_loop:
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mov rax, 0 ; syscall: read
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mov rdi, 0 ; fd = stdin
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lea rsi, [rbx + rcx] ; buf + offset
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mov rdx, r14
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sub rdx, rcx ; remaining = max_len - bytes_read
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syscall
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cmp rax, 0
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je .done_read
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js .read_error
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add rcx, rax
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cmp rcx, r14
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jl .read_loop
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.done_read:
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; push len (rcx) then addr (rbx)
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sub r12, 16
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mov [r12], rcx
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mov [r12 + 8], rbx
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ret
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.read_error:
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; return negative errno in rax, addr = 0
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sub r12, 16
|
|
mov [r12], rax
|
|
mov qword [r12 + 8], 0
|
|
ret
|
|
|
|
.fail_mmap:
|
|
sub r12, 16
|
|
mov qword [r12], -1
|
|
mov qword [r12 + 8], 0
|
|
ret
|
|
ret
|
|
word_main:
|
|
; push 1024
|
|
sub r12, 8
|
|
mov qword [r12], 1024
|
|
call word_read_stdin
|
|
call word_dup
|
|
; push 0
|
|
sub r12, 8
|
|
mov qword [r12], 0
|
|
call word__3e
|
|
mov rax, [r12]
|
|
add r12, 8
|
|
test rax, rax
|
|
jz L_if_false_0
|
|
call word_write_buf
|
|
; push 0
|
|
sub r12, 8
|
|
mov qword [r12], 0
|
|
call word_exit
|
|
L_if_false_0:
|
|
; push str_0
|
|
sub r12, 8
|
|
mov qword [r12], str_0
|
|
; push 17
|
|
sub r12, 8
|
|
mov qword [r12], 17
|
|
call word_puts
|
|
call word_exit
|
|
ret
|
|
section .data
|
|
data_start:
|
|
str_0: db 114, 101, 97, 100, 95, 115, 116, 100, 105, 110, 32, 102, 97, 105, 108, 101, 100, 0
|
|
str_0_len equ 17
|
|
data_end:
|
|
section .bss
|
|
align 16
|
|
dstack: resb DSTK_BYTES
|
|
dstack_top:
|
|
align 16
|
|
rstack: resb RSTK_BYTES
|
|
rstack_top:
|
|
align 16
|
|
print_buf: resb PRINT_BUF_BYTES
|
|
print_buf_end: |