Intel 210200-002 manual DAS Decimal Adjust DAS For Subtraction, 1001011111

DAS DECIMAL ADJUST DAS

FOR SUBTRACTION

Operation:

if «AL) & OFH) >9 or (AF) = 1 then (AL) +- (AL) - 6

(AF) -1

if (AL) >9FH or (CF) = 1 then

(AL) - (AL) - 60H

(CF) -1

Flags Affected:

AF, CF, PF, SF, ZF. OF undefined

Description:

DAS (Decimal Adjust for Subtraction) cor- rects the result of a previous subtraction of two valid packed decimal operands (the desti- nation operand must have beenspt;cified as register AL). DAS changes the content of AL to a pair of valid packed decimal digits. DAS updates AF. CF. PF. SF and ZF; the content of OF is undefined following execution of DAS.

Encoding:

1001011111

DAS Operands Clocks Transfers Bytes DAS Coding Example

(no operands) 4 - 1 DAS

2-71