Maintenance script: Initial automated import

2016-02-05T22:06:58Z

Initial automated import

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CP is a subtraction from A that doesn't update A, only the flags it would have set/reset if it really was subtracted.

== Syntax ==

CP op8

op8 is any one of the allowed inputs.

'''Allowed instructions'''

cp a
cp b
cp c
cp d
cp e
cp h
cp l
cp ixh
cp ixl
cp iyh
cp iyl
cp (ix+n)
cp (iy+n)
cp n ;8 bit constant

== Effects ==

C, S, and Z flags modified by definition
P/V detects overflow

== Uses ==

Here are some general rules on using CP

=== Unsigned ===

If A == N, then Z flag is set.
If A != N, then Z flag is reset.
If A < N, then C flag is set.
If A >= N, then C flag is reset.

=== Signed ===

If A == N, then Z flag is set.
If A != N, then Z flag is reset.
If A < N, then S and P/V are different.
A >= N, then S and P/V are the same.

== T-States ==
r denotes 8-bit register.

{| class="wikitable"
| r || 4
|-
| X || 7
|-
| (hl) || 7
|-
| (ix+X) || 19
|-
| (iy+X) || 19
|}

== See also ==

[[Z80:Opcodes:BIT|BIT]],[[Z80:Opcodes:CALL|CALL]],[[Z80:Opcodes:CPD|CPD]],[[Z80:Opcodes:CPDR|CPDR]],[[Z80:Opcodes:CPI|CPI]],[[Z80:Opcodes:CPIR|CPIR]],[[Z80:Opcodes:JP|JP]],[[Z80:Opcodes:JR|JR]],[[Z80:Opcodes:RET|RET]]

{{lowercase}}
[[Category:Z80 Assembly]]
[[Category:Z80 Heaven]]
[[Category:Z80 Opcodes]]

Z80:Opcodes:CP - Revision history

Maintenance script: Initial automated import