Maxim Integrated MAXQ610 - Manual (Page 191)

14-24
MAXQ610 User’s Guide
SRA4 Operation: 15 Active Accumulator (Acc) 0 Carry Flag
→ → →
Acc .[11:0] ← Acc .[15:4]
Acc .[15:12] ← Acc .15
C ← Acc .3
Encoding: 15 0
1000 1010 1011 1010
Example(s): ; Acc = 9878h, C=0, Z=0
SRA4 ; Acc = F987h, C=1, Z=0
SRA4 ; Acc = FF98h, C=0, Z=0
SUB/SUBB src Subtract/Subtract with Borrow
Description: Subtracts the specified src from the active accumulator (Acc) and returns the result back to the active
accumulator . The SUBB additionally subtracts the borrow (Carry Flag) which may have resulted from
previous subtraction . For the complete list of src specifiers, reference the MOVE instruction . The
PFX[n] register may be used to supply the high byte of data for 8-bit sources .
Status Flags: C, S, Z, OV
SUB
Operation:
Acc ← Acc – src
Encoding: 15 0
f101 1010 ssss ssss
Example(s): ; Acc = 2345h to start, A[1]= 1250h
SUB A[1] ; Acc = 10F5h, C=0, S=0, Z=0, OV=0
SUB A[1] ; Acc = FEA5h, C=1, S=1, Z=0, OV=0
SUB A[2] ; A[2] =7FFFh
;
→ Acc = 7EA6h; C=0, S=0, Z=0, OV=1
SUBB
Operation:
Acc ← Acc – (src + C)
Encoding: 15 0
f111 1010 ssss ssss
Example(s): ; Acc = 2345h, A[1]= 1250h, C=1
SUBB A[1] ; Acc = 10F4h, C=0, S=0, Z=0
SUBB A[1] ; Acc = FEA4h, C=1, S=1, Z=0
Special Notes: The active accumulator (Acc) is not allowed as the src for these operations .