Difference between revisions of "PM Opc SHR"
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Latest revision as of 12:51, 27 March 2010
SHR = Shift Right
Hex | Mnemonic | Cycles |
---|---|---|
CE 8C | SHR A | 12 |
CE 8D | SHR B | 12 |
CE 8E nn | SHR [N+#nn] | 20 |
CE 8F | SHR [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
; SHR Ds ; ; Ds = Source/Destination Ds = Ds SHR 1
Description
"8-Bits Destination" bits are shifted right by 1.
NOTE: This instruction can be used as an unsigned integer division by 2.
Conditions
Zero: Set when result is 0
Carry: Set when the old bit 0 was 1
Sign: Set when bit 7 of the result is 1
Overflow remain unchanged
Examples
; A = 0x04 (4) SHR A ; A = 0x02 (2) ; F = (Zero=0):(Carry=0):(Sign=0)
; B = 0x45 (69) SHR B ; B = 0x22 (34) ; F = (Zero=0):(Carry=1):(Sign=0)
; B = 0x84 (132) SHR B ; B = 0x42 (66) ; F = (Zero=0):(Carry=0):(Sign=0)
; [HL] = 0x01 (1) SHR [HL] ; [HL] = 0x00 (0) ; F = (Zero=1):(Carry=1):(Sign=0)