HT47C20 Holtek Semiconductor Inc, HT47C20 Datasheet - Page 53

• Manufacturer Part Number: HT47C20
• Description: 8-Bit Microcontroller
• Manufacturer: Holtek Semiconductor Inc

SUB A,x
Description
Operation
Affected flag(s)
SWAP [m]
Description
Operation
Affected flag(s)
SWAPA [m]
Description
Operation
Affected flag(s)
SZ [m]
Description
Operation
Affected flag(s)
Subtract immediate data from accumulator
The immediate data specified by the code is subtracted from the contents
of the accumulator, leaving the result in the accumulator.
ACC ¬ ACC+x+1
Swap nibbles within the data memory
The low-order and high-order nibbles of the specified data memory (one
of the data memories) are interchanged.
[m].3~[m].0 « [m].7~[m].4
Swap data memory and place result in accumulator
The low-order and high-order nibbles of the specified data memory are
interchanged, writing the result to the accumulator. The contents of the
data memory remain unchanged.
ACC.3~ACC.0 ¬ [m].7~[m].4
ACC.7~ACC.4 ¬ [m].3~[m].0
Skip if data memory is zero
If the contents of the specified data memory is zero, the following instruc-
tion, fetched during the current instruction execution, is discarded and a
dummy cycle is replaced to get the proper instruction. This is a 2-cycle in-
struction. Otherwise proceed with the next instruction.
Skip if [m]=0
TC2
TC2
TC2
TC2
¾
¾
¾
¾
TC1
TC1
TC1
TC1
¾
¾
¾
¾
TO
TO
TO
TO
¾
¾
¾
¾
53
PD
PD
PD
PD
¾
¾
¾
¾
OV
OV
OV
OV
¾
¾
¾
Ö
¾
¾
¾
Z
Ö
Z
Z
Z
AC
AC
AC
AC
¾
¾
¾
Ö
¾
¾
¾
C
C
C
C
Ö
January 18, 2000
HT47C20