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47 lines
1.3 KiB
ArmAsm
47 lines
1.3 KiB
ArmAsm
# strchr() Author: Kees J. Bot 1 Jan 1994
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# char *strchr(const char *s, int c)
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# Look for a character in a string.
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.intel_syntax
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.globl _strchr
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.text
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.align 16
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_strchr:
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push ebp
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mov ebp, esp
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push edi
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cld
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mov edi, [ebp+8] # edi = string
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mov edx, 16 # Look at small chunks of the string
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next:
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shl edx, 1 # Chunks become bigger each time
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mov ecx, edx
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xorb al, al # Look for the zero at the end
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repne scasb
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pushf # Remember the flags
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sub ecx, edx
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neg ecx # Some or all of the chunk
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sub edi, ecx # Step back
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movb al, [ebp+12] # The character to look for
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repne scasb
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je found
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popf # Did we find the end of string earlier?
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jne next # No, try again
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xor eax, eax # Return NULL
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pop edi
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pop ebp
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ret
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found:
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pop eax # Get rid of those flags
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lea eax, [edi-1] # Address of byte found
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pop edi
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pop ebp
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ret
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