Preliminary
HT48R06A-1
SBC A,[m]
Subtract data memory and carry from the accumulator
Description
The contents of the specified data memory and the complement of the carry
flag are subtracted from the accumulator, leaving the result in the accumula-
tor.
Operation
ACC ¬ ACC+[m]+C
Affected flag(s)
TC2 TC1 TO PD OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SBCM A,[m]
Subtract data memory and carry from the accumulator
Description
The contents of the specified data memory and the complement of the carry
flag are subtracted from the accumulator, leaving the result in the data
memory.
Operation
[m] ¬ ACC+[m]+C
Affected flag(s)
TC2 TC1 TO PD OV
Z
AC
C
¾
¾
¾
¾
Ö
Ö
Ö
Ö
SDZ [m]
Skip if decrement data memory is zero
Description
The contents of the specified data memory are decremented by one. If the re-
sult is zero, the next instruction is skipped. If the result is zero, the following
instruction, fetched during the current instruction execution, is discarded
and a dummy cycle is replaced to get the proper instruction (two cycles). Oth-
erwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]-1)=0, [m] ¬ ([m]-1)
Affected flag(s)
TC2 TC1 TO PD OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
SDZA [m]
Decrement data memory and place result in ACC, skip if zero
Description
The contents of the specified data memory are decremented by one. If the re-
sult is zero, the next instruction is skipped. The result is stored in the accu-
mulator but the data memory remains unchanged. If the result is zero, the
following instruction, fetched during the current instruction execution, is
discarded and a dummy cycle is replaced to get the proper instruction (two
cycles). Otherwise proceed with the next instruction (one cycle).
Operation
Skip if ([m]-1)=0, ACC ¬ ([m]-1)
Affected flag(s)
TC2 TC1 TO PD OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
¾
38
February 25, 2000
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
