## 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
CE BF nn | CMP N, #nn | 12

### Execute

    #nn     = Immediate unsigned 8-Bits
    #ss     = Immediate signed 8-Bits
    A       = Register A
    B       = Register B
    N       = Register N
    [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

    (discarded) = Sc2 - Sc

### Description

"8-Bits Source 2" subtracts with "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)

Sign: Set when bit 7 of the result 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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