[sdcc-devel] [ sdcc-Bugs-1617503 ] pic16, printf, problem with "%b"

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Bugs item #1617503, was opened at 2006-12-17 21:08
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Frieder Ferlemann (frief)
Assigned to: Nobody/Anonymous (nobody)
Summary: pic16, printf, problem with "%b"

Initial Comment:
there are 2 problems related to %b on pic16.
(%b is used to output at number at base 2 there)

- buffer[16] is too small (would have to be 
  at least 17 or 33 bytes)

- there's a "%b" clash with the other ports. 
  %b is used as a length indicator there and 
  specifies that only one byte is popped of the stack.

Both uses are not ANSI/ISO C standard, so may be difficult to decide for either one.

I'd suggest to consider dropping the "binary" 
output format option for pic16 printf though, 
because 

a) it doesn't seem to be in wide-spread use 
   (we'd otherwise probably have complaints
   about the buffer overflow)

b) the additional resource use (33 bytes instead 
   of 12 bytes which would be needed for a buffer
   for long octal) seems huge. 
   Even gcc/glibc don't offer this format
   so why should an embedded device?

c) there's a name clash within SDCC. And yet 
   another nonstd letter would be needed for 
   the byte popping functionality.
   (%hh is not equivalent to %b as popps an int
   and just outputs as char)

Would it do harm to just remove it?
(device/lib/pic16/libc/stdio/vfprintf.c line 121:
else if(*ch == 'b')radix = 2;)

Greetings,
Frieder

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