73 lines
1.2 KiB
NASM
73 lines
1.2 KiB
NASM
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;***
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;llshl.asm - long shift left
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;
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; Copyright (c) Microsoft Corporation. All rights reserved.
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;
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;Purpose:
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; define long shift left routine (signed and unsigned are same)
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; __allshl
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;
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;*******************************************************************************
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include hal.inc
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;***
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;llshl - long shift left
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;
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;Purpose:
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; Does a Long Shift Left (signed and unsigned are identical)
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; Shifts a long left any number of bits.
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;
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;Entry:
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; EDX:EAX - long value to be shifted
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; CL - number of bits to shift by
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;
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;Exit:
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; EDX:EAX - shifted value
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;
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;Uses:
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; CL is destroyed.
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;
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;Exceptions:
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;
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;*******************************************************************************
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__allshl PROC NEAR
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;
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; Handle shifts of 64 or more bits (all get 0)
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;
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cmp cl, 64
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jae short RETZERO
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;
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; Handle shifts of between 0 and 31 bits
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;
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cmp cl, 32
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jae short MORE32
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shld edx,eax,cl
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shl eax,cl
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ret
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;
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; Handle shifts of between 32 and 63 bits
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;
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MORE32:
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mov edx,eax
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xor eax,eax
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and cl,31
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shl edx,cl
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ret
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;
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; return 0 in edx:eax
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;
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RETZERO:
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xor eax,eax
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xor edx,edx
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ret
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__allshl ENDP
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end
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