1989_MELPS_7700_Software_Manual

CPX Compare Memory and Index Register X CPX
Operation
X - M
Description
Subtracts the contents of memory from the contents of the index register X. The
index register X and memory contents are not changed.
Status flags
IPL :
N
V
m
x
o
I
Not affected.
Set to 1 when bit 15 (or bit 7 if the index register length selection flag x is set
to 1) of the operation result is 1. Otherwise, cleared to O.
Not affected.
Not affected.
Not affected.
Not affected.
Not affected.
Z Set to 1 when the result of operation is O. Otherwise, cleared to O.
C Set to 1 if the result of operation is 0 or larger. Otherwise, cleared to O.
Addressing mode Syntax Machine code Bytes Cycles
Immediate CPX #imm EOl6, imm 2 2
Direct CPX dd E416, dd 2 4
Absolute CPX mmll ECl6, II, mm 3 4
(Note1) When operating on 16·bit data in the immediate addressing mode with the index register length
selection flag x set to 0, the bytes-count increases by 1.
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