Post by thread:Convert byte to ascii

-----Original Message----- From: Justin Grimm <.....eclipseKILLspam@spam@ACCESSIN.COM.AU> >Hi piclisters >I need a short routine that will convert a single byte >to 3 ascii bytes > >For example; if the number 127 (decimal) is in file x, >how can I convert it to 3 registers (hundreds,tens and units). >This is what the 3 files should have in them after the conversion > register1 = 31, register2 = 32, register3 = 37 (all in ascii >notation) a = 127 b = a mod 10 +48 a = a /10 c = a mod 10 + 48 a = a /10 d = a+48 Is the way it is done. The bad part is the number is in reverse order. The way I do it is to start at the right hand side of the string and return a pointer to the first character. Here it is in C char *i2a(int n, int base, char delim, int format) { char *s; char *cp; int count; s = scratch; count =0; cp = s + 7; /* start at end of string */ *cp-- = 0; /* terminate string */ *cp-- = delim; while(n) { *cp-- = hex_str[n % base]; n =n / base; count++; } while(count< format) { *cp-- = '0'; count++; } s=cp+1; return s; } good luck Gordon Gordon Couger gcougerKILLspamcouger.com Stillwater, OK 405 624-2855 GMT -6:00

Gordon Couger wrote: {Quote hidden}> > -----Original Message----- > From: Justin Grimm <.....eclipseKILLspam.....ACCESSIN.COM.AU> > > >Hi piclisters > >I need a short routine that will convert a single byte > >to 3 ascii bytes > > > >For example; if the number 127 (decimal) is in file x, > >how can I convert it to 3 registers (hundreds,tens and units). > >This is what the 3 files should have in them after the conversion > > register1 = 31, register2 = 32, register3 = 37 (all in ascii > >notation) > > a = 127 > b = a mod 10 +48 > a = a /10 > c = a mod 10 + 48 > a = a /10 > d = a+48 > Is the way it is done. The bad part is the number is in reverse order. The > way I do it is to start at the right hand side of the string and return a > pointer > to the first character. I was going to point you to the Archive, but for some reason it stops at April '98. Here's something that I posted last May. It only converts the numbers to BCD, but going to ascii is trivial. (Does any one have this stuff referenced on a web page)? -------------------------------------------------------------- Here's a 24-instruction solution with a little looping: Explanation: anick.simplenet.com/piclist/Oct97/0369.html Code: http://anick.simplenet.com/piclist/Oct97/0312.html It's based on what Payson affectionately calls his 'wonderful 16-bit binary to BCD algorithm': www.iversoft.com/cgi-bin/lwgate/PICLIST/archives/March97/date/article-0.h tml (This link is from the archive and takes a while to download. It's been a year since it's been posted, perhaps it's time again?) Here's the 28-cycle (non-looping) version that I promised yesterday. It's based on binary comparisons. It's one of those routines that is very difficult to comment. So I didn't. However it takes advantage of this little trick to quickly ascertain the ones' digit: If you look at the ones' digit for 2^N you see this pattern: n = 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11 ... 2^n % 10 = 1, 2, 4, 8, 6, 2, 4, 8, 6, 2, 4, 8 ... If it wasn't for the annoying 6's, you could simply sum the nibbles to get and get the ones' digit (after a relatively simple binary to BCD conversion). However, it's simple enough to test if bit 4, 8,... are high and to subtract 1 and then add 6 (or simply add 5) if they are. The second observation is that the sum of all of the tens' digits is less than 16, and thus can fit into one nibble. This simplifies having to deal with overflow until after all of the digits have been added together. The third observation is that the BCD result is greater than 200 only if the most significant bit is set. ;******************************** ;binary_to_bcd - 8-bits ; ;Input ; bin - 8-bit binary number ;Outputs ; hundreds - the hundreds digit of the BCD conversion ; tens_and_ones - the tens and ones digits of the BCD conversion binary_to_bcd: CLRF hundreds SWAPF bin,W ADDWF bin,W ANDLW 00001111b SKPNDC ADDLW 0x16 SKPNDC ADDLW 0x06 ADDLW 0x06 SKPDC ADDLW -0x06 BTFSC bin,4 ADDLW 0x16 - 1 + 0x6 SKPDC ADDLW -0x06 BTFSC bin,5 ADDLW 0x30 BTFSC bin,6 ADDLW 0x60 BTFSC bin,7 ADDLW 0x20 ADDLW 0x60 RLF hundreds,F BTFSS hundreds,0 ADDLW -0x60 MOVWF tens_and_ones BTFSC bin,7 INCF hundreds,F Scott

this a little fragmetn of code to ASCII convert movfw ind ; get value from register xorlw 0x30 ; format to ASCII movwf _char ; put to char_register call lcd_char ; send to display and here a routine for conversion of value in L_byte to 5 digits in R0( MSD ), R 1, R2 (LSD ) bin_bcd bcf status,0 movlw .16 movwf count clrf R0 clrf R1 clrf R2 loop16 rlf L_byte rlf H_byte rlf R2 rlf R1 rlf R0 decfsz count goto adjDEC retlw 0 adjDEC clrwdt movlw R2 movwf fsr call adjBCD movlw R1 movwf fsr call adjBCD movlw R0 movwf fsr call adjBCD goto loop16 adjBCD movlw 3 addwf indf,w movwf temp btfsc temp,3 movwf indf movlw 30 addwf indf,w movwf temp btfsc temp,7 movwf 0 retlw 0 good luke Scott Dattalo wrote: > Gordon Couger wrote: > > > > {Original Message removed}