Difference between revisions of "PM Opc SAL"
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Latest revision as of 12:50, 27 March 2010
SAL = Shift Arithmetic Left
Hex | Mnemonic | Cycles |
---|---|---|
CE 80 | SAL A | 12 |
CE 81 | SAL B | 12 |
CE 82 nn | SAL [N+#nn] | 20 |
CE 83 | SAL [HL] | 16 |
Execute
A = Register A B = Register B [N+#nn] = Memory: (I shl 16) or (N shl 8) or #nn [HL] = Memory: (I shl 16) or HL
; SAL Ds ; ; Ds = Source/Destination Ds = Ds SHL 1
Description
"8-Bits Destination" bits are arithmetically shifted left by 1.
NOTE: This instruction can be used as an signed integer multiplication by 2.
Conditions
Zero: Set when result is 0
Carry: Set when the old bit 7 was 1
Overflow: Set when result overflow 8-bits signed range (< -128 OR > 127)
Sign: Set when bit 7 of the result is 1
Examples
; A = 0x04 (4) SAL A ; A = 0x08 (8) ; F = (Zero=0):(Carry=0):(Overflow=0):(Sign=0)
; A = 0xFE (-2) SAL A ; A = 0xFC (-4) ; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=1)
; B = 0x45 (69) SAL B ; B = 0x8A (-124) ; F = (Zero=0):(Carry=0):(Overflow=1):(Sign=1)
; B = 0x84 (-124) SAL B ; B = 0x14 (20) ; F = (Zero=0):(Carry=1):(Overflow=1):(Sign=0)
; [HL] = 0x80 (-128) SAL [HL] ; [HL] = 0x00 (0) ; F = (Zero=1):(Carry=1):(Overflow=1):(Sign=0)