SAR = Shift Arithmetic Right
| Hex | Mnemonic | Cycles |
|---|---|---|
| CE 88 | SAR A | 12 |
| CE 89 | SAR B | 12 |
| CE 8A nn | SAR [N+#nn] | 20 |
| CE 8B | SAR [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
; SAR Ds
;
; Ds = Source/Destination
Ds = (Ds AND 0x80) OR (Ds SHR 1)
Description
"8-Bits Destination" bits are arithmetically shifted right by 1.
NOTE: This instruction can be used as an signed integer division by 2.
Conditions
Zero: Set when result is 0
Carry: Set when the old bit 0 was 1
Overflow: Always Reset (there's never a overflow)
Sign: Set when bit 7 of the result is 1
Examples
; A = 0x04 (4)
SAR A
; A = 0x02 (2)
; F = (Zero=0):(Carry=0):(Overflow=0):(Sign=0)
; A = 0xFD (-4)
SAR A
; A = 0xFE (-2)
; F = (Zero=0):(Carry=0):(Overflow=0):(Sign=1)
; B = 0x45 (69)
SAR B
; B = 0x22 (34)
; F = (Zero=0):(Carry=1):(Overflow=0):(Sign=0)
; B = 0x84 (-124)
SAR B
; B = 0xC2 (-62)
; F = (Zero=0):(Carry=0):(Overflow=0):(Sign=1)
; [HL] = 0x01 (1)
SAR [HL]
; [HL] = 0x00 (0)
; F = (Zero=1):(Carry=1):(Overflow=0):(Sign=0)