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)