C8051F360/1/2/3/4/5/6/7/8/9
11.7.2. Multiply Only Example
The example below implements the equation:
4660
×
– 292 = – 1360720
MOV
MOV
MOV
MOV
MOV
NOP
NOP
MAC0CF,
MAC0AH,
MAC0AL,
MAC0BH,
MAC0BL,
#01h
#12h
#34h
#FEh
#DCh
; Use integer numbers, and multiply only mode (add to zero)
; Load MAC0A register with 1234 hex = 4660 decimal
; Load MAC0B register with FEDC hex = -292 decimal
; This line initiates the Multiply operation
;
;
;
;
After this instruction, the Accumulator should be equal to
FFFFEB3CB0 hex = -1360720 decimal. The MAC0STA register should
be 0x01, indicating a negative result.
After this instruction, the Rounding register is updated
NOP
11.7.3. MAC0 Accumulator Shift Example
The example below shifts the MAC0 accumulator left one bit, and then right two bits:
MOV
MOV
MOV
MOV
MOV
MOV
NOP
NOP
MOV
MOV
NOP
NOP
MAC0OVR, #40h
MAC0ACC3, #88h
MAC0ACC2, #44h
MAC0ACC1, #22h
MAC0ACC0, #11h
MAC0CF, #20h
; The next few instructions load the accumulator with the value
; 4088442211 Hex.
MAC0CF, #30h
MAC0CF, #30h
;
;
;
;
;
;
;
Initiate a Left-shift
After this instruction, the accumulator should be 0x8110884422
The rounding register is updated after this instruction
Initiate a Right-shift
Initiate a second Right-shift
After this instruction, the accumulator should be 0xE044221108
The rounding register is updated after this instruction
Rev. 1.0
121
SILABS [ SILICON LABORATORIES ]
