PIC18C858-E/L Microchip Technology, PIC18C858-E/L Datasheet - Page 72

• Manufacturer Part Number: PIC18C858-E/L
• Description: IC MCU OTP 16KX16 CAN 84PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 18Cr

Specifications of PIC18C858-E/L

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 68
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: OTP
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 84-PLCC
• For Use With: AC164310 - MODULE SKT FOR PM3 84PLCCDVA18XL840 - ADAPTER DEVICE ICE 84PLCCAC174012 - MODULE SKT PROMATEII 84PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Other names: PIC18C858E/L

6.1
Example 6-1 shows the sequence to perform an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
Example 6-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s most significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 6-1:
EXAMPLE 6-2:
PIC18CXX8
MOVFF
MULWF
MOVFF
MULWF
BTFSC
SUBWF
MOVFF
BTFSC
SUBWF
DS30475A-page 72
Operation
ARG1, WREG
ARG2
ARG1, WREG
ARG2
ARG2, SB
PRODH, F
ARG2, WREG
ARG1, SB
PRODH, F
8 x 8 UNSIGNED MULTIPLY
ROUTINE
8 x 8 SIGNED MULTIPLY
ROUTINE
;
; ARG1 * ARG2 ->
;
PRODH:PRODL
; ARG1 * ARG2 ->
; PRODH:PRODL
; Test Sign Bit
; PRODH = PRODH
;
; Test Sign Bit
; PRODH = PRODH
;
- ARG1
- ARG2
Advanced Information
Example 6-3 shows the sequence to perform a 16 x 16
unsigned multiply. Equation 6-1 shows the algorithm
that is used. The 32-bit result is stored in 4 registers
RES3:RES0.
EQUATION 6-1:
EXAMPLE 6-3:
RES3:RES0
;
;
;
MOVFF
MULWF
MOVFF
MOVFF
MOVFF
MULWF
MOVFF
MOVFF
MOVFF
MULWF
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
MOVFF
MULWF
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
=
=
ARG1L, WREG
ARG2L
PRODH, RES1
PRODL, RES0
ARG1H, WREG
ARG2H
PRODH, RES3
PRODL, RES2
ARG1L, WREG
ARG2H
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
ARG1H, WREG
ARG2L
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
ARG1H:ARG1L • ARG2H:ARG2L
(ARG1H • ARG2H • 2
(ARG1H • ARG2L • 2
(ARG1L • ARG2H • 2
(ARG1L • ARG2L)
16 x 16 UNSIGNED
MULTIPLY ROUTINE
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
 2000 Microchip Technology Inc.
; ARG1L * ARG2L ->
;
;
;
; ARG1H * ARG2H ->
;
;
;
; ARG1L * ARG2H ->
;
;
; Add cross
;
;
;
;
;
; ARG1H * ARG2L ->
;
;
; Add cross
;
;
;
;
PRODH:PRODL
PRODH:PRODL
PRODH:PRODL
PRODH:PRODL
products
products
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