Maxim Integrated MAXQ7666 - Manual (Page 367)

MAXQ7665/MAXQ7666 User’s Guide
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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 accumula-
tor. 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 MAXQ7665/MAXQ7666 may use the
PFX[n] register 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
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
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.
f101 1010 ssss ssss
f111 1010 ssss ssss
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