168 lines
2.5 KiB
Plaintext
168 lines
2.5 KiB
Plaintext
; The OS/K Team licenses this file to you under the MIT license.
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; See the LICENSE file in the project root for more information.
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;
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; int strtol(const char *str, int base)
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;
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; rax = integer extracted from str
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; rdx = pointer to first invalid byte
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;
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strtol:
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mov ax2, 1
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jmp strtoq
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;
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; int strtoul(const char *str, int base)
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;
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; rax = integer extracted from str
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; rdx = pointer to first invalid byte
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;
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strtoul:
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nul ax2
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jmp strtoq
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;
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; int strtoq(const char *str, int base, bool signed)
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;
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; guesses base when 'base'=0
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;
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strtoq:
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nul rax, rsi
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mov rdx, ax0
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; make sure base is in [2, 32]
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beq ax1, 1, .bad
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bltu 36, ax1, .bad
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; empty string?
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bzr b[rdx], .done
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.skip_spc:
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bne b[rdx], ' ', .no_spc
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inc rdx, 1
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jmp .skip_spc
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.no_spc:
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; skip +
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bne b[rdx], '+', .no_plus
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inc rdx, 1
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.no_plus:
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; unsigned?
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bzr ax2, .unsigned
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; parse '-'
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bne b[rdx], '-', .unsigned
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inc rdx, 1
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mov rsi, 1
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.unsigned:
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; base 0
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bzr ax1, .base_0
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; base prefix?
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bne b[rdx], '0', .main_loop
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inc rdx, 1
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movzx rcx, b[rdx]
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; "0x"/"0b" prefix
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jrcxz .done ; "0"
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beq rcx, 'x', .parsed_0x
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beq rcx, 'b', .parsed_0b
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; may be octal, but we don't care
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; we accept "0110101010" (despite base=2) for instance
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jmp .main_loop
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.parsed_0x:
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; are we in base 16?
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; if not, leave rax = 0 and *rdx = 'x'
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bne ax1, 16, .done
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; else
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inc rdx, 1
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jmp .main_loop
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.parsed_0b:
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; are we in base 2?
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; if not, leave rax = 0 and *rdx = 'b'
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bne ax1, 2, .done
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; else
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inc rdx, 1
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jmp .main_loop
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.base_0:
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; guess base
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beq b[rdx], '0', .b0_not10
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; must be base 10
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mov ax1, 10
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jmp .main_loop
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.b0_not10:
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inc rdx, 1
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bne b[rdx], 'x', .b0_not16
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inc rdx, 1
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mov ax1, 16
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jmp .main_loop
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.b0_not16:
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bne b[rdx], 'b', .b0_not2
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inc rdx, 1
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mov ax1, 2
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jmp .main_loop
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.b0_not2:
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; take octal by default
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mov ax1, 8
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.main_loop:
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movzx rcx, b[rdx]
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inc rdx, 1
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; between 0 and 9?
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bltu rcx, '0', .done
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bltu '9', rcx, .not_digit10
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; yes
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dec rcx, '0'
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jmp .next
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.not_digit10:
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bltu rcx, 'A', .done
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bltu 'Z', rcx, .not_digitAZ
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dec rcx, 55 ; 'A' - 10
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jmp .next
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.not_digitAZ:
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bltu rcx, 'a', .done
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bltu 'z', rcx, .done
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dec rcx, 87 ; 'a' - 10
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jmp .next
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.next:
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; too large for base?
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blteu ax1, rcx, .done
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mul rax, ax1
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inc rax, rcx
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jmp .main_loop
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.done:
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; negative?
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bzr rsi, .r
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; yes
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neg rax
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.r:
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ret
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.bad:
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ret
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