PIC17C4X
Compare f with WREG,
DAW
Decimal Adjust WREG Register
[label] DAW f,s
CPFSLT
skip if f < WREG
[ label ] CPFSLT
0 ≤ f ≤ 255
Syntax:
Operands:
Syntax:
f
0 ≤ f ≤ 255
Operands:
Operation:
s
[0,1]
(f) – (WREG),
skip if (f) < (WREG)
(unsigned comparison)
If [WREG<3:0> >9] .OR. [DC = 1] then
WREG<3:0> + 6 → f<3:0>, s<3:0>;
else
Operation:
WREG<3:0> → f<3:0>, s<3:0>;
Status Affected:
Encoding:
None
If [WREG<7:4> >9] .OR. [C = 1] then
WREG<7:4> + 6 → f<7:4>, s<7:4>
else
0011
0000
ffff
ffff
Compares the contents of data memory
location 'f' to the contents of WREG by
performing an unsigned subtraction.
Description:
WREG<7:4> → f<7:4>, s<7:4>
Status Affected:
Encoding:
C
If the contents of 'f' < the contents of
WREG, then the fetched instruction is
discarded and an NOP is executed
instead making this a two-cycle instruc-
tion.
0010
111s
ffff
ffff
DAW adjusts the eight bit value in
WREG resulting from the earlier addi-
tion of two variables (each in packed
BCD format) and produces a correct
packed BCD result.
Description:
Words:
Cycles:
1
1 (2)
s = 0: Result is placed in Data
memory location 'f' and
Q Cycle Activity:
Q1
WREG.
Q2
Q3
Q4
s = 1: Result is placed in Data
memory location 'f'.
Decode
Read
register 'f'
Execute
NOP
Words:
Cycles:
1
1
If skip:
Q1
Q2
Q3
Q4
Forced NOP
NOP
Execute
NOP
Q Cycle Activity:
Q1
Q2
Q3
Q4
HERE
NLESS
LESS
CPFSLT REG
Example:
Decode
Read
Execute
Write
:
:
register 'f'
register 'f'
and other
specified
register
Before Instruction
PC
W
=
=
Address (HERE)
?
DAW
REG1, 0
Example1:
After Instruction
If REG
PC
If REG
PC
<
=
≥
=
WREG;
Address (LESS)
WREG;
Before Instruction
WREG
REG1
C
=
=
=
=
0xA5
??
0
Address (NLESS)
DC
0
After Instruction
WREG
REG1
C
=
=
=
=
0x05
0x05
1
DC
0
Example 2:
Before Instruction
WREG
REG1
C
=
=
=
=
0xCE
??
0
DC
0
After Instruction
WREG
REG1
C
=
=
=
=
0x24
0x24
1
DC
0
DS30412C-page 120
1996 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
