The attached routine by Peter Hemsley, March 2003, does not return the
correct conversion. As an example I am trying to convert decimal 12345
to binary, and it returns hex 31 in the high byte and hex D4 in the
low byte. I checked several on-line converters and they all return
the answer hex 31 in the high byte and hex 39 in the low byte. I
am using MPLAB ver 8.1, and am using a PICKit 2 in debug run the
program and to check the result. To test it I just added a couple of
lines to pre-load the numbers. Here is the listing . . .
; 5 digit decimal to 16 (17) bit binary. By Peter Hemsley, March
2003.
; Input decimal digits in D0 (LSD) to D4 (MSD)
; Output 16 bit binary in NUMHI and NUMLO
; No temporary variables required
; Code size: 33 instructions
; Execution time: 33 cycles (excluding Call and Return)
; Returns carry set if > 65535 (and NUMHI-LO MOD 65536)
LIST pF870 ;tell assembler what chip we are using
include "P16F870.inc" ;include the defaults for the chip
ERRORLEVEL 0, -302 ;suppress bank selection messages
__config 0x3F71 ;sets the configuration settings (oscillator type etc.)
cblock 0x20
NUMLO
NUMHI
D0
D1
D2
D3
D4
endc
org 0x00
; dec2bin16
movlw 0x01
movwf D0
movlw 0x02
movwf D1
movlw 0x03
movwf D2
movlw 0x04
movwf D3
movlw 0x05
movwf D4
movf D1,W ; (D1 + D3) * 2
addwf D3,W
movwf NUMLO
rlf NUMLO,F
swapf D2,W ; + D2 * 16 + D2
addwf D2,W
addwf NUMLO,F
rlf D4,W ; + (D4 * 2 + D3) * 256
addwf D3,W
movwf NUMHI
rlf NUMLO,F ; * 2
rlf NUMHI,F
swapf D3,W ; - D3 * 16
subwf NUMLO,F
skpc
decf NUMHI,F
swapf D2,W ; + D2 * 16 + D1
addwf D1,W
addwf NUMLO,F
skpnc
incf NUMHI,F
swapf D4,W ; + D4 * 16 + D0
addwf D0,W
rlf NUMLO,F ; * 2
rlf NUMHI,F
addwf NUMLO,F
skpnc
incf NUMHI,F
movf D4,W ; - D4 * 256
subwf NUMHI,F
swapf D4,W ; + D4 * 16 * 256 * 2
addwf NUMHI,F
addwf NUMHI,F
loop
goto loop
end
NUMHI returns hex 31 and NUMLO returns hex D4. All I used was the
cblock and simple move instructions to load the values.
I really need a routine like this to convert 5 digit decimal to binary
. . .
HELP
Ken