Re: [Sdcc-user] floating point calculation

[Jesus Calvino-F. <Je...@ec...>]

Works fine here.  Below is my test program.  The results compiling using 
MSVC 6 and sdcc follow.  What version of sdcc are you using.  What was your 
command line?

----- fp.c test program -----
#include <stdio.h>
#include <string.h>
#ifdef SDCC_mcs51
#include <8052.h>
#endif

void main(void)
{
         float result;
         unsigned char I_HI;
         unsigned char F_HI;
         char buff[10], j;

         printf("Test begins...\n");
         for(I_HI=1, F_HI=63; I_HI<220; I_HI+=11)
         {
             result= 54.2535 * ((float) (I_HI) + (float) (F_HI) / 65536);

                 //Prepare the floating point result for display using 
three decimal digits
                 sprintf(buff, "%ld", (long)(result*1000));
                 j=strlen(buff);
                 buff[j+1]=0;
                 buff[j]=buff[j-1];
                 buff[j-1]=buff[j-2];
                 buff[j-2]=buff[j-3];
                 buff[j-3]='.';

             printf("I_HI=%d, F_HI=%d, result=%s\n", I_HI, F_HI, buff);
         }
         printf("Test completed...\n");
}

#ifdef SDCC_mcs51
unsigned char _sdcc_external_startup(void)
{
   TR1=0;
   TMOD=(TMOD&0x0f)|0x20;
   PCON|=0x80;
   TH1=TL1=0xfd; //38400 baud with 22MHz crystal
   TR1=1;
   SCON=0x52;

   return 0;
}

char getchar(void)
{
   char c;
   while (!RI);
   RI=0;
   c=SBUF;
   return c;
}

void putchar(char c)
{
   while (!TI);
   TI=0;
   SBUF=c;
   if (c=='\n') putchar('\r');
}
#endif

----- fp.c End of test program -----

If compiled with MSVC (usinc cl fp.c) this is the output:

C:\sdcc\tests>fp
Test begins...
I_HI=1, F_HI=63, result=54.305
I_HI=12, F_HI=63, result=651.094
I_HI=23, F_HI=63, result=1247.882
I_HI=34, F_HI=63, result=1844.671
I_HI=45, F_HI=63, result=2441.459
I_HI=56, F_HI=63, result=3038.248
I_HI=67, F_HI=63, result=3635.036
I_HI=78, F_HI=63, result=4231.825
I_HI=89, F_HI=63, result=4828.613
I_HI=100, F_HI=63, result=5425.402
I_HI=111, F_HI=63, result=6022.190
I_HI=122, F_HI=63, result=6618.979
I_HI=133, F_HI=63, result=7215.767
I_HI=144, F_HI=63, result=7812.556
I_HI=155, F_HI=63, result=8409.344
I_HI=166, F_HI=63, result=9006.133
I_HI=177, F_HI=63, result=9602.921
I_HI=188, F_HI=63, result=10199.710
I_HI=199, F_HI=63, result=10796.498
I_HI=210, F_HI=63, result=11393.287
Test completed...

If compiled using sdcc (using sdcc fp.c) and ran from an AT89S53 this is 
the output I got in HyperTerminal:

Test begins...
I_HI=1, F_HI=63, result=54.305
I_HI=12, F_HI=63, result=651.094
I_HI=23, F_HI=63, result=1247.882
I_HI=34, F_HI=63, result=1844.671
I_HI=45, F_HI=63, result=2441.459
I_HI=56, F_HI=63, result=3038.248
I_HI=67, F_HI=63, result=3635.036
I_HI=78, F_HI=63, result=4231.825
I_HI=89, F_HI=63, result=4828.614
I_HI=100, F_HI=63, result=5425.402
I_HI=111, F_HI=63, result=6022.191
I_HI=122, F_HI=63, result=6618.979
I_HI=133, F_HI=63, result=7215.768
I_HI=144, F_HI=63, result=7812.556
I_HI=155, F_HI=63, result=8409.345
I_HI=166, F_HI=63, result=9006.134
I_HI=177, F_HI=63, result=9602.922
I_HI=188, F_HI=63, result=10199.711
I_HI=199, F_HI=63, result=10796.499
I_HI=210, F_HI=63, result=11393.287
Test completed...

By the way, this is the version of sdcc I used:

C:\sdcc\tests>sdcc -v
SDCC : mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08 
2.5.1 #1
040 (Jun  1 2005) (MSVC)

At 08:57 AM 6/6/2005, you wrote:

>Hello
>
>I'm building a project using a 87c52 mcu and the SDCC compiler.
>
>I have a need to solve this equation:
>
>result= 54.2535 * ((float) (I_HI) + (float) (F_HI) / 65536);
>
>I have declared the variables as:
>
>float result;
>unsigned char I_HI;
>unsigned char F_HI;
>
>I have compiled a program in MS C++ to solve this equation and it works 
>fine, but using SDCC it doesn't. I don't know if the problem lies with the 
>mcu, the code , SDCC or all of the above
>
>Anybody has any advice I'll appreciate it
>
>Thanks
>Jim Peterson


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