Cmpw – NEC 78K/0 Series User Manual
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CHAPTER 5 EXPLANATION OF INSTRUCTIONS
User's Manual U12326EJ4V0UM
Compare Word
CMPW
Word Data Comparison
[Instruction format]
CMPW dst, src
[Operation]
dst – src
[Operand]
Mnemonic
Operand(dst,src)
CMPW
AX, #word
[Flag]
Z
AC
CY
Ч
Ч
Ч
[Description]
•
The source operand (src) specified by the 2nd operand is subtracted from the destination operand (dst)
specified by the 1st operand.
The subtraction result is not stored anywhere and only the Z, AC and CY flags are changed.
•
If the subtraction result is 0, the Z flag is set (1). In all other cases, the Z flag is cleared (0).
•
If the subtraction generates a borrow out of bit 15, the CY flag is set (1). In all other cases, the CY flag is
cleared (0).
•
As a result of subtraction, the AC flag becomes undefined.
[Description example]
CMPW AX, #ABCDH;
ABCDH is subtracted from the AX register and only the flags are changed (comparison
of the AX register and the immediate data).