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Sign Extension Table
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|
| CBW ; o16 98 [8086]
| CWD ; o16 99 [8086]
| CDQ ; o32 99 [0x386]
| CWDE ; o32 98 [0xo386]


CBW : Extends AL into AX by repeating the top bit of AL in every bit of AH
CWD : Extends AX into DX: AX by repating the top bit of AX throughout DX
CWDE : Extends EAX into EDX:EAX

so if AL was (binary format) 10000000
and we did CBQ would AH = 11111111?

Anybdoy got a fine example of what this would be good for?
Posted on 2002-04-22 10:44:15 by Volcano_88101
; main purpose of instruction

cdq
idiv ebx

Posted on 2002-04-22 10:54:49 by bitRAKE