HT46R47
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 0.
Description
The contents of the specified data memory are decremented by 1. If the result
is 0, the next instruction is skipped. If the result is 0, the following instruc-
tion, fetched during the current instruction execution, is discarded and a
dummy cycle is replaced to get the proper instruction (2 cycles). Otherwise
proceed with the next instruction (1 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 0.
Description
The contents of the specified data memory are decremented by 1. If the result
is 0, the next instruction is skipped. The result is stored in the accumulator
but the data memory remains unchanged. If the result is 0, the following in-
struction, fetched during the current instruction execution, is discarded and
a dummy cycle is replaced to get the proper instruction (2 cycles). Otherwise
proceed with the next instruction (1 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
Rev. 1.40
39
July 18, 2001
ETC [ ETC ]
