Texas Instruments TMS320C28x, Reference Manual

Page: 188 / 695

ADDB AX, #8bitSigned
6-31
ADDB AX, #8bitSigned Add 8-bit Constant to AX
SYNTAX OPTIONS OPCODE OBJMODE RPT CYC
ADDB AX, #8bitSigned
1001 110A CCCC CCCC
X − 1
Operands AX Accumulator high (AH) or accumulator low (AL) register
#8bit-
Signed
8-bit immediate signed 2s complement constant value (-128 to 127)
Description Add the sign extended 8-bit constant to the specified AX register (AH
or AL) and store the result in the AX register:
AX = AX + S:8bit;
Flags and
Modes
N After the addition, AX is tested for a negative condition. If bit 15 of AX is 1,
then the negative flag bit is set; otherwise it is cleared.
Z
After the addition, AX is tested for a zero condition. The zero flag bit is set if
the operation results in AX = 0, otherwise it is cleared
C If the addition generates a carry, C is set; otherwise C is cleared.
V If an overflow occurs, V is set; otherwise V is not affected. Signed positive
overflow occurs if the result crosses the max positive value (0x7FFF) in the
positive direction. Signed negative overflow occurs if the result crosses the
max negative value (0x8000) in the negative direction.
Repeat This instruction is not repeatable. If this instruction follows the RPT
instruction, it resets the repeat counter (RPTC) and executes only
once.
Example
; Add 2 to VarA and subtract 3 from VarB:
MOV AL,@VarA ; Load AL with contents of VarA
ADDB AL,#2 ; Add to AL the value 0x0002 (2)
MOV @VarA,AL ; Store result in VarA
MOV AL,@VarB ; Load AL with contents of VarB
ADDB AL,#−3 ; Add to AL the value 0xFFFD (−3)
MOV @VarB,AL ; Store result in VarB