Intel 8XC251SA, User Manual

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A-45
INSTRUCTION SET REFERENCE
Hex Code in: Binary Mode = [Encoding]
Source Mode = [Encoding]
Operation: CLR
(CY)
←
0
CLR bit
Binary Mode Source Mode
Bytes: 4 4
States: 4† 3†
†If this instruction addresses a port (P x , x = 0–3), add 2 states.
[Encoding]
Hex Code in: Binary Mode = [A5][Encoding]
Source Mode = [Encoding]
Operation: CLR
(bit)
←
0
CMP <dest>,<src>
Function: Compare
Description: Subtracts the source operand from the destination operand. The result is not stored in the
destination operand. If a borrow is needed for bit 7, the CY (borrow) flag is set; otherwise it is
clear.
When subtracting signed integers, the OV flag indicates a negative result when a negative
value is subtracted from a positive value, or a positive result when a positive value is
subtracted from a negative value.
Bit 7 in this description refers to the most significant byte of the operand (8, 16, or 32 bit)
The source operand allows four addressing modes: register, direct, immediate and indirect.
Flags:
Example: Register 1 contains 0C9H (11001001B) and register 0 contains 54H (01010100B). The
instruction
CMP R1,R0
clears the CY and AC flags and sets the OV flag.
Variations
CMP Rmd,Rms
Binary Mode Source Mode
Bytes: 3 2
States: 2 1
1 0 1 0 1 0 0 1 1 1 0 0 0 y y y dir addr
CY AC OV N Z
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