mirror of
https://gitlab.os-k.eu/os-k-team/kvisc.git
synced 2023-08-25 14:05:46 +02:00
112 lines
1.6 KiB
Plaintext
112 lines
1.6 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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; char *_itoa(char *buf, int num, int base, int unsi)
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;
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; Acts as itoa if unsi == 0, as utoa otherwise
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;
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_itoa:
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mov rax, ax0
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xor rdx, rdx
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; make sure base is in [2, 32]
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cmp ax2, 2
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jmp.b .bad
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cmp ax2, 36
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jmp.a .bad
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; deal with zero
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test ax1, ax1
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jmp.z .zero
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; deal with base 10 signedness
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test ax3, ax3 ; unsigned mode
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jmp.nz .conv
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cmp ax2, 10 ; base 10
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jmp.nz .conv
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cmp ax1, -9223372036854775808 ; LONG_MIN
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jmp.z .min
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sgn rdx, ax1 ; extract ax1 sign
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cmp rdx, -1 ; negative?
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not.z ax1 ; -x = ~x+1
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inc.z ax1 ; need "neg" inst...
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; main loop
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.conv:
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test ax1, ax1
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jmp.z .fini
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mov rsx, ax1
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mod rsx, ax2 ; ax1 % base
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cmp rsx, 9 ; rsx > 9 ?
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jmp.a .nondec
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add rsx, 48 ; '0'
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jmp .next
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.nondec:
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add rsx, 87 ; 'a' - 10
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.next:
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mov b[ax0], rsx
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inc ax0
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div ax1, ax2
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jmp .conv
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; add minus flag, null-terminate and reverse
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.fini:
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cmp rdx, -1
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mov.z b[ax0], 45 ; '-'
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inc.z ax0
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mov b[ax0], 0
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mov ax0, rax
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call strrev2
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ret
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;
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; exceptional cases
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;
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.bad:
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mov q[errno], EINVAL
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mov b[rax], 0
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ret
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.zero:
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mov b[ax0], 48 ; '0'
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mov b[ax0+1], 0
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ret
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.min:
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mov ax1, .min10
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call strcpy
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ret
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.min10 = "-9223372036854775808"
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;
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; wrappers
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;
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itoa:
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mov ax3, 0
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jmp _itoa
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utoa:
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mov ax3, 1
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jmp _itoa
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