PM Opc CMP8

CMP = Compare (8-Bits)

Hex	Mnemonic	Cycles
30	CMP A, A	8
31	CMP A, B	8
32 nn	CMP A, #nn	8
33	CMP A, [HL]	8
34 nn	CMP A, [N+#nn]	12
35 nn nn	CMP A, [#nnnn]	16
36	CMP A, [X]	8
37	CMP A, [Y]	8
DB nn nn	CMP [N+#nn], #nn	16
CE 30 ss	CMP A, [X+#ss]	16
CE 31 ss	CMP A, [Y+#ss]	16
CE 32	CMP A, [X+L]	16
CE 33	CMP A, [Y+L]	16
CE 34	CMP [HL], A	16
CE 35 nn	CMP [HL], #nn	20
CE 36	CMP [HL], [X]	20
CE 37	CMP [HL], [Y]	20
CE BC nn	CMP B, #nn	12
CE BD nn	CMP L, #nn	12
CE BE nn	CMP H, #nn	12

Execute

#nn     = Immediate unsigned 8-Bits
#ss     = Immediate signed 8-Bits
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
[X]     = Memory: (XI shl 16) or X
[Y]     = Memory: (YI shl 16) or Y
[#nnnn] = Memory: (I shl 16) or #nnnn
[X+#ss] = Memory: (XI shl 16) or (X + #ss)
[Y+#ss] = Memory: (YI shl 16) or (Y + #ss)
[X+L]   = Memory: (XI shl 16) or (X + signed(L))
[Y+L]   = Memory: (YI shl 16) or (Y + signed(L))

; CMP Sc2, Sc
;
; Sc2 = Source 2
; Sc = Source
; Ds = Result is discarded

Ds = Sc2 - Sc

Description

8-Bits Source subtracts to the 8-Bits 2nd Source, Output 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)

Sign: Set when 7th bit is 1

Examples

; A = 0x55
CMP A, $80
; A = 0x55
;     0xD5 (0x55 - 0x80 = 0x(1)D4)
; F = (Zero = 0):(Carry = 0):(Overflow=1):(Sign=1)

; B = 0x31
; A = 0xCF
CMP A, B
; B = 0x31
; A = 0xCF
;     0x9E (0xCF - 0x31 = 0x(0)9E)
; F = (Zero = 0):(Carry = 0):(Overflow=0):(Sign=0)

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