rfivet/stm32bringup
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zero padding and uppercase/lowercase for hexadecimal.

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This commit is contained in:
Renaud 2020-12-17 11:03:48 +08:00
parent 788c5c5b3b
commit d2617fbb0b
1 changed files with 27 additions and 11 deletions
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38
printf.c
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@ -5,18 +5,25 @@
#include <stdio.h>
#include "system.h" /* kputc(), kputs() */
static int kputu( unsigned u, unsigned d) {
static int kputu( unsigned u, unsigned d, int padlen, char fmt) {
char s[ 12] ; /* room for 11 octal digit + EOS */
char *p = &s[ sizeof s - 1] ; /* point to last byte */
*p = 0 ; /* null terminated string */
fmt = fmt & 0x20 ; /* set uppercase bit */
do {
unsigned r = u % d ;
u /= d ;
*--p = "0123456789ABCDEF"[ r] ;
*--p = "0123456789ABCDEF"[ r] | fmt ;
padlen -= 1 ;
} while( u) ;
return kputs( p) ;
while( padlen-- > 0) {
kputc( '0') ;
u += 1 ; /* use u to calculate output length */
}
return u + kputs( p) ;
}
static int kputi( int i) {
@ -26,7 +33,7 @@ static int kputi( int i) {
kputc( '-') ;
}
return flag + kputu( i, 10) ;
return flag + kputu( i, 10, 0, 'u') ;
}
int printf( const char *fmt, ...) {
@ -38,23 +45,31 @@ int printf( const char *fmt, ...) {
while( ( c = *fmt++) != 0)
if( c != '%') {
cnt += 1 ; kputc( c) ;
} else if( ( c = *fmt++) == 0) {
cnt += 1 ; kputc( '%') ;
break ;
} else
} else {
int len = 0 ;
c = *fmt++ ;
while( c >= '0' && c <= '9') {
len = len * 10 + ( c - '0') ;
c = *fmt++ ;
}
if( c == 0)
break ;
switch( c) {
case 'c':
cnt += 1 ; kputc( va_arg( ap, int /* char */)) ;
break ;
case 'o':
cnt += kputu( va_arg( ap, unsigned), 8) ;
cnt += kputu( va_arg( ap, unsigned), 8, len, c) ;
break ;
case 'u':
cnt += kputu( va_arg( ap, unsigned), 10) ;
cnt += kputu( va_arg( ap, unsigned), 10, len, c) ;
break ;
case 'x':
case 'X':
cnt += kputu( va_arg( ap, unsigned), 16) ;
cnt += kputu( va_arg( ap, unsigned), 16, len, c) ;
break ;
case 'i':
case 'd':
@ -69,6 +84,7 @@ int printf( const char *fmt, ...) {
case '%':
cnt += 1 ; kputc( c) ;
}
}
va_end( ap) ;
return cnt ;