Pokémon mini Development Documentation

CP = Compare (8-bits)

Hex	Mnemonic	Cycles
30	CP A,A	2
31	CP A,B	2
32 nn	CP A,#nn	2
33	CP A,[HL]	2
34 ll	CP A,[BR:ll]	3
35 ll hh	CP A,[hhll]	4
36	CP A,[IX]	2
37	CP A,[IY]	2
DB ll nn	CP [BR:ll],#nn	4
CE 30 dd	CP A,[IX+dd]	4
CE 31 dd	CP A,[IY+dd]	4
CE 32	CP A,[IX+L]	4
CE 33	CP A,[IY+L]	4
CE 34	CP [HL],A	4
CE 35 nn	CP [HL],#nn	5
CE 36	CP [HL],[IX]	5
CE 37	CP [HL],[IY]	5
CE BC nn	CP B,#nn	3
CE BD nn	CP L,#nn	3
CE BE nn	CP H,#nn	3
CE BF nn	CP BR,#nn	3

Execute

#nn     = Immediate unsigned 8-bits
dd      = Immediate signed 8-bits
A       = Register A
B       = Register B
BR      = Register BR
[BR:ll] = Memory: (EP shl 16) or (BR shl 8) or #nn
[HL]    = Memory: (EP shl 16) or HL
[IX]    = Memory: (XP shl 16) or IX
[IY]    = Memory: (YP shl 16) or IY
[hhll]  = Memory: (EP shl 16) or hhll
[IX+dd] = Memory: (XP shl 16) or (IX + dd)
[IY+dd] = Memory: (YP shl 16) or (IY + dd)
[IX+L]  = Memory: (XP shl 16) or (IX + signed(L))
[IY+L]  = Memory: (YP shl 16) or (IY + signed(L))

; CP Sc2, Sc
;
; Sc2 = Source 2
; Sc  = Source

(discarded) = Sc2 - Sc

Description

Subtracts “8-bits Source 2” from “8-bits Source”, result is discarded.

This instruction is used to compare values.

Conditions

Zero: Set when result is 0
Carry: Set when result is < 0
Overflow: Set when result overflow 8-bits signed range (< -128 OR > 127)
Negative: Set when bit 7 of the result is 1

Examples

; A = 0x55
CP A, $80
; A = 0x55
;     0xD5 (0x55 - 0x80 = 0x(1)D4)
; SC = (Zero=0):(Carry=0):(Overflow=1):(Negative=1)

; B = 0x31
; A = 0xCF
CP A, B
; B = 0x31
; A = 0xCF
;     0x9E (0xCF - 0x31 = 0x(0)9E)
; SC = (Zero=0):(Carry=0):(Overflow=0):(Negative=0)

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