74 lines
1.0 KiB
Plaintext
74 lines
1.0 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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; void strrev(char *buf, const char *str)
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;
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; buf and src must NOT overlap
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;
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strrev:
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test b[ax1], b[ax1]
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cmovz b[ax0], 0
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cretz
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; save str's location
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mov rdx, ax1
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; go to str's end, just before
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; the null terminator
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.1:
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test b[ax1+1], b[ax1+1]
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cincnz ax1
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cjmpnz .1
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.2:
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; copy, going backward though str
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; and forward through buf
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mov b[ax0], b[ax1]
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cmp ax1, rdx
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cmovz b[ax0+1], 0
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cretz
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inc ax0
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dec ax1
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jmp .2
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;
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; void strrev2(char *str)
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;
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; Inverses str
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;
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strrev2:
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test b[ax0], b[ax0]
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cretz
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mov ax1, ax0
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; go to str's end, just before
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; the null terminator
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.1:
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test b[ax1+1], b[ax1+1]
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cincnz ax1
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cjmpnz .1
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; increase ax0 while decreasing ax1, performing exchanges
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.2:
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cmp ax0, ax1
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cjmpae .3
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xchg b[ax0], b[ax1]
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inc ax0
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dec ax1
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jmp .2
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.3:
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ret
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