Rainbow Electronics HT49R70A-1 User Manual
Page 36
RRCA [m]
Rotate right through carry and place result in the accumulator
Description
Data of the specified data memory and the carry flag are rotated 1 bit right. Bit 0 replaces
the carry bit and the original carry flag is rotated into the bit 7 position. The rotated result is
stored in the accumulator. The contents of the data memory remain unchanged.
Operation
ACC.i
¬ [m].(i+1); [m].i:bit i of the data memory (i=0~6)
ACC.7
¬ C
C
¬ [m].0
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
¾
¾
¾
Ö
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 sub-
tracted from the accumulator, leaving the result in the accumulator.
Operation
ACC
¬ ACC+[m]+C
Affected flag(s)
TC2
TC1
TO
PD
OV
Z
AC
C
¾
¾
¾
¾
Ц
Ц
Ц
Ц
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 sub-
tracted 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
Ц
Ц
Ц
Ц
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 instruction, fetched during the current
instruction execution, is discarded and a dummy cycle is replaced to get the proper instruc-
tion (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 instruction, fetched during the current instruction
execution, is discarded and a dummy cycle is replaced to get the proper instruction (2 cy-
cles). 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
HT49R70A-1
Rev. 1.00
36
December 4, 2001