41 lines
1.5 KiB
NASM
41 lines
1.5 KiB
NASM
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; pentbug.asm
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;
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; tests for the existence of the well-documented Pentium NPU bug
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;
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; assemble and run this program using Borland's TASM and run under DOS:
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;
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; TASM pentbug ; one pass assemble
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; TLINK /Tdc pentbug ; link as COM file
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; PENTBUG ; run the program...
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;
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.MODEL tiny
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.386
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.387
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.CODE
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ORG 100h
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Start:
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mov dx,OFFSET okmsg ; start out optimistically
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fild [first] ; load the first number (x)
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fild [second] ; and the second (y)
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fdiv st(1),st ; perform y/x
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fmulp st(1),st ; now st(0) = (y/x)*x
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fild [first] ; reload y
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fcompp ; compare the two
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fnstsw ax ; put status word into ax
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sahf ; load into CPU flags
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jz short @@NoBug ; if they're equal, no bug
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mov dx,OFFSET bugmsg ; load bad news message...
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@@NoBug:
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mov ah,9 ; print appropriate message
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int 21h ;
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mov ah,4ch ; and exit
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int 21h ;
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first DD 4195835 ; "magic numbers" culled from
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second DD 3145727 ; the net. There are others...
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okmsg DB "No "
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bugmsg DB "Pentium bug found.",13,10,'$'
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END Start
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