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Individual Instruction Descriptions
4-92
4.14.11 CMPB Compare Two Bytes
Syntax
[label] name src, src1
Clock,
clk
Word,
w
With RPT,
clk
Class
CMPB A
n
,
imm8
1 1 N/R 2a
CMPB R
x
,
imm8
1 1 N/R 4b
Execution status flags set by
src
–
src1
byte
PC ⇐ PC + 1
Flags Affected
src
is A
n
:OF, SF, ZF, CF are set accordingly
src
is R
x
: RCF, RZF are set accordingly
Opcode
Instructions 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
CMPB A
n
,
imm8
1 0 1 0 0 1 1 A
n imm8
CMPB R
x
,
imm8
1 0 1 1 1 1
k4 k3 k2 k7 k6 k5
R
x k1 k0
Description Subtract value of
src1
(zero filled in upper 8 bits) from
src
(i.e.,
src
–
src1
) and
only modify the status flags. Contents of
src
not changed.
See Also CMP, CMPS, J
cc
, C
cc
Example 4.14.11.1 CMPB A0, 0xf3
Compare immediate value 0xf3 to accumulator A0.
Example 4.14.11.2 CMPB R3, 0x21
Compare immediate value 0x21 to R3.