Pokémon mini Development Documentation

RR = Rotate Right through Carry

Hex	Mnemonic	Cycles
CE 98	RR A	3
CE 99	RR B	3
CE 9A ll	RR [BR:ll]	5
CE 9B	RR [HL]	4

Execute

A       = Register A
B       = Register B
[BR:ll] = Memory: (EP shl 16) or (BR shl 8) or #nn
[HL]    = Memory: (EP shl 16) or HL

; RR Ds
;
; Ds = Source/Destination

Ds = (Ds SRL 1) OR (Carry SLL 7)

Description

“8-bits Destination” bits are rotated right by 1 through Carry.

Conditions

• Zero: Set when result is 0
• Carry: Set when old bit 0 is 1
• Negative: Set when bit 7 of the result is 1

Overflow remains unchanged

Examples

; A = 0x04
; SC = (Carry=0)
RR A
; A = 0x02
; SC = (Zero=0):(Carry=0):(Negative=0)

; B = 0x45
; SC = (Carry=1)
RR B
; B = 0xA2
; SC = (Zero=0):(Carry=1):(Negative=0)

; B = 0x84
; SC = (Carry=0)
RR B
; B = 0x42
; SC = (Zero=0):(Carry=0):(Negative=0)

; [HL] = 0x01
; SC = (Carry=0)
RR [HL]
; [HL] = 0x00
; SC = (Zero=1):(Carry=1):(Negative=0)

; [HL] = 0x01
; SC = (Carry=1)
RR [HL]
; [HL] = 0x80
; SC = (Zero=0):(Carry=1):(Negative=1)

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