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Date: Wed, 31 May 2023 16:15:48 +0200
From: Jens Gustedt <Jens.Gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: [C23 128 bit 2/4] C23: implement w128 and wf128 support for printf
C23 now allows extended integer types wider than `intmax_t` for the
case that they are used to implement some fixed-width integer
type. The length specifer wN can then be used for `printf` and friends
to print the type.
Gcc and clang provide `__int128` types for many architectures (in
particular x86_64) since a long time, and adding these types
"officially" is a recurrent user request. They are particularly nice
to have for bitsets.
Implementing w128 (and wf128) is a first step to provide `int128_t`
and `uint128_t` natively, independently of the fact if there already
is a compiler that implements these types.
This implementation hopefully only adds a very mild overhead in size
and processing time for those architectures where this type is
present. The impact is
- one extra state array for the 128 bit type (some 60 static byte or so)
- a widening of the local buffer needed to collect digits (512 bytes
on the stack)
- widening of the static format functions to accept the 128 type
(probably some byte for some extra load instructions)
These functions then are possibly a bit slower, since they use wider
instructions and/or combine several instructions. There was already an
optimization in place for the 'u' format, because here division and
modulo base 10 is needed, which could be a bit costly. We now apply
similar tricks for the other integer formats to avoid passing into the
128 bit emulation if that is possible.
---
src/stdio/vfprintf.c | 113 ++++++++++++++++++++++++++----------------
src/stdio/vfwprintf.c | 45 ++++++++++-------
2 files changed, 97 insertions(+), 61 deletions(-)
diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index a531a513..aac065fc 100644
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -1,4 +1,5 @@
#include "stdio_impl.h"
+#include "uwide128.h"
#include <errno.h>
#include <ctype.h>
#include <limits.h>
@@ -35,10 +36,12 @@ enum {
BARE, LPRE, LLPRE, HPRE, HHPRE, BIGLPRE,
ZTPRE, JPRE, WPRE,
STOP,
+ WWPRE,
PTR, INT, UINT, ULLONG,
LONG, ULONG,
SHORT, USHORT, CHAR, UCHAR,
LLONG, SIZET, IMAX, UMAX, PDIFF, UIPTR,
+ INT128, UINT128,
DBL, LDBL,
NOARG,
MAXSTATE
@@ -114,7 +117,7 @@ static const unsigned char states[]['z'-'A'+1] = {
union arg
{
- uintmax_t i;
+ uwide128 i;
long double f;
void *p;
};
@@ -122,22 +125,24 @@ union arg
static void pop_arg(union arg *arg, int type, va_list *ap)
{
switch (type) {
- case PTR: arg->p = va_arg(*ap, void *);
- break; case INT: arg->i = va_arg(*ap, int);
- break; case UINT: arg->i = va_arg(*ap, unsigned int);
- break; case LONG: arg->i = va_arg(*ap, long);
- break; case ULONG: arg->i = va_arg(*ap, unsigned long);
- break; case ULLONG: arg->i = va_arg(*ap, unsigned long long);
- break; case SHORT: arg->i = (short)va_arg(*ap, int);
- break; case USHORT: arg->i = (unsigned short)va_arg(*ap, int);
- break; case CHAR: arg->i = (signed char)va_arg(*ap, int);
- break; case UCHAR: arg->i = (unsigned char)va_arg(*ap, int);
- break; case LLONG: arg->i = va_arg(*ap, long long);
- break; case SIZET: arg->i = va_arg(*ap, size_t);
- break; case IMAX: arg->i = va_arg(*ap, intmax_t);
- break; case UMAX: arg->i = va_arg(*ap, uintmax_t);
- break; case PDIFF: arg->i = va_arg(*ap, ptrdiff_t);
- break; case UIPTR: arg->i = (uintptr_t)va_arg(*ap, void *);
+ case PTR: arg->p = va_arg(*ap, void *);
+ break; case INT: arg->i = __uwide128_i64(va_arg(*ap, int));
+ break; case UINT: arg->i = __uwide128_u64(va_arg(*ap, unsigned int));
+ break; case LONG: arg->i = __uwide128_i64(va_arg(*ap, long));
+ break; case ULONG: arg->i = __uwide128_u64(va_arg(*ap, unsigned long));
+ break; case ULLONG: arg->i = __uwide128_u64(va_arg(*ap, unsigned long long));
+ break; case SHORT: arg->i = __uwide128_i64((short)va_arg(*ap, int));
+ break; case USHORT: arg->i = __uwide128_u64((unsigned short)va_arg(*ap, int));
+ break; case CHAR: arg->i = __uwide128_i64((signed char)va_arg(*ap, int));
+ break; case UCHAR: arg->i = __uwide128_u64((unsigned char)va_arg(*ap, int));
+ break; case LLONG: arg->i = __uwide128_i64(va_arg(*ap, long long));
+ break; case SIZET: arg->i = __uwide128_u64(va_arg(*ap, size_t));
+ break; case IMAX: arg->i = __uwide128_i64(va_arg(*ap, intmax_t));
+ break; case UMAX: arg->i = __uwide128_u64(va_arg(*ap, uintmax_t));
+ break; case PDIFF: arg->i = __uwide128_i64(va_arg(*ap, ptrdiff_t));
+ break; case UIPTR: arg->i = __uwide128_u64((uintptr_t)va_arg(*ap, void *));
+ break; case INT128: arg->i = __uwide128_pop(ap);
+ break; case UINT128: arg->i = __uwide128_pop(ap);
break; case DBL: arg->f = va_arg(*ap, double);
break; case LDBL: arg->f = va_arg(*ap, long double);
}
@@ -163,29 +168,51 @@ static const char xdigits[16] = {
"0123456789ABCDEF"
};
-static char *fmt_x(uintmax_t x, char *s, int lower)
+static char *fmt_u(unsigned long long x, char *s)
{
- for (; x; x>>=4) *--s = xdigits[(x&15)]|lower;
+ unsigned long y;
+ for ( ; x>ULONG_MAX; x/=10) *--s = '0' + x%10;
+ for (y=x; y; y/=10) *--s = '0' + y%10;
return s;
}
-static char *fmt_b(uintmax_t x, char *s)
+static char *fmt128_x(uwide128 x, char *s, int lower)
{
- for (; x; x>>=1) *--s = '0' + (x&1);
+ uint32_t y;
+ uint64_t z;
+ while (x.v64[hi64]) *--s = xdigits[__uwide128_div16(&x)]|lower;
+ for (z = x.v64[lo64]; z>UINT32_MAX; z>>=4) *--s = xdigits[(z&15)]|lower;
+ for (y=z; y; y>>=4) *--s = xdigits[(y&15)]|lower;
return s;
}
-static char *fmt_o(uintmax_t x, char *s)
+static char *fmt128_b(uwide128 x, char *s)
{
- for (; x; x>>=3) *--s = '0' + (x&7);
+ uint64_t z;
+ uint32_t y;
+ while (x.v64[hi64]) *--s = '0' + __uwide128_div2(&x);
+ for (z = x.v64[lo64]; z>UINT32_MAX; z>>=1) *--s = '0' + z%2;
+ for (y=z; y; y>>=1) *--s = '0' + y%2;
return s;
}
-static char *fmt_u(uintmax_t x, char *s)
+static char *fmt128_o(uwide128 x, char *s)
{
- unsigned long y;
- for ( ; x>ULONG_MAX; x/=10) *--s = '0' + x%10;
- for (y=x; y; y/=10) *--s = '0' + y%10;
+ uint64_t z;
+ uint32_t y;
+ while (x.v64[hi64]) *--s = '0' + __uwide128_div8(&x);
+ for (z = x.v64[lo64]; z>UINT32_MAX; z>>=3) *--s = '0' + z%8;
+ for (y=z; y; y>>=3) *--s = '0' + y%8;
+ return s;
+}
+
+static char *fmt128_u(uwide128 x, char *s)
+{
+ uint64_t z;
+ uint32_t y;
+ while (x.v64[hi64]) *--s = '0' + __uwide128_div10(&x);
+ for (z = x.v64[lo64]; z>UINT32_MAX; z/=10) *--s = '0' + z%10;
+ for (y=z; y; y/=10) *--s = '0' + y%10;
return s;
}
@@ -456,7 +483,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
unsigned st, ps, width=0;
int cnt=0, l=0;
size_t i;
- char buf[sizeof(uintmax_t)*CHAR_BIT+3+LDBL_MANT_DIG/4];
+ char buf[sizeof(uwide128)*CHAR_BIT+3+LDBL_MANT_DIG/4];
const char *prefix;
int t, pl;
wchar_t wc[2], *ws;
@@ -498,7 +525,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
if (isdigit(s[1]) && s[2]=='$') {
l10n=1;
if (!f) nl_type[s[1]-'0'] = INT, w = 0;
- else w = nl_arg[s[1]-'0'].i;
+ else w = nl_arg[s[1]-'0'].i.v64[lo64];
s+=3;
} else if (!l10n) {
w = f ? va_arg(*ap, int) : 0;
@@ -511,7 +538,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
if (*s=='.' && s[1]=='*') {
if (isdigit(s[2]) && s[3]=='$') {
if (!f) nl_type[s[2]-'0'] = INT, p = 0;
- else p = nl_arg[s[2]-'0'].i;
+ else p = nl_arg[s[2]-'0'].i.v64[lo64];
s+=4;
} else if (!l10n) {
p = f ? va_arg(*ap, int) : 0;
@@ -552,6 +579,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
#else
case 64: ps = LLPRE; st = (st == UINT) ? ULLONG : ((st == INT) ? LLONG : PTR); break;
#endif
+ case 128: ps = WWPRE; st = (st == UINT) ? UINT128 : ((st == INT) ? INT128 : PTR); break;
default: goto inval;
}
@@ -592,6 +620,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
case HHPRE: *(unsigned char *)arg.p = cnt; break;
case ZTPRE: *(size_t *)arg.p = cnt; break;
case JPRE: *(uintmax_t *)arg.p = cnt; break;
+ case WWPRE: *(uwide128 *)arg.p = __uwide128_i64(cnt); break;
}
continue;
case 'p':
@@ -599,39 +628,39 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
t = 'x';
fl |= ALT_FORM;
case 'x': case 'X':
- a = fmt_x(arg.i, z, t&32);
- if (arg.i && (fl & ALT_FORM)) prefix+=(t>>4), pl=2;
+ a = fmt128_x(arg.i, z, t&32);
+ if (!__uwide128_iszero(arg.i) && (fl & ALT_FORM)) prefix+=(t>>4), pl=2;
if (0) {
case 'b': case 'B':
- a = fmt_b(arg.i, z);
- if (arg.i && (fl & ALT_FORM)) prefix = (t == 'b' ? "0b" : "0B"), pl=2;
+ a = fmt128_b(arg.i, z);
+ if (!__uwide128_iszero(arg.i) && (fl & ALT_FORM)) prefix = (t == 'b' ? "0b" : "0B"), pl=2;
} if (0) {
case 'o':
- a = fmt_o(arg.i, z);
+ a = fmt128_o(arg.i, z);
if ((fl&ALT_FORM) && p<z-a+1) p=z-a+1;
} if (0) {
case 'd': case 'i':
pl=1;
- if (arg.i>INTMAX_MAX) {
- arg.i=-arg.i;
+ if (arg.i.v64[hi64]>INT64_MAX) {
+ arg.i=__uwide128_neg(arg.i);
} else if (fl & MARK_POS) {
prefix++;
} else if (fl & PAD_POS) {
prefix+=2;
} else pl=0;
case 'u':
- a = fmt_u(arg.i, z);
+ a = fmt128_u(arg.i, z);
}
if (xp && p<0) goto overflow;
if (xp) fl &= ~ZERO_PAD;
- if (!arg.i && !p) {
+ if (__uwide128_iszero(arg.i) && !p) {
a=z;
break;
}
- p = MAX(p, z-a + !arg.i);
+ p = MAX(p, z-a + __uwide128_iszero(arg.i));
break;
case 'c':
- *(a=z-(p=1))=arg.i;
+ *(a=z-(p=1))=arg.i.v64[lo64];
fl &= ~ZERO_PAD;
break;
case 'm':
@@ -644,7 +673,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg,
fl &= ~ZERO_PAD;
break;
case 'C':
- wc[0] = arg.i;
+ wc[0] = arg.i.v64[lo64];
wc[1] = 0;
arg.p = wc;
p = -1;
diff --git a/src/stdio/vfwprintf.c b/src/stdio/vfwprintf.c
index 3689c2d5..d510233f 100644
--- a/src/stdio/vfwprintf.c
+++ b/src/stdio/vfwprintf.c
@@ -1,4 +1,5 @@
#include "stdio_impl.h"
+#include "uwide128.h"
#include <errno.h>
#include <ctype.h>
#include <limits.h>
@@ -28,10 +29,12 @@ enum {
BARE, LPRE, LLPRE, HPRE, HHPRE, BIGLPRE,
ZTPRE, JPRE, WPRE,
STOP,
+ WWPRE,
PTR, INT, UINT, ULLONG,
LONG, ULONG,
SHORT, USHORT, CHAR, UCHAR,
LLONG, SIZET, IMAX, UMAX, PDIFF, UIPTR,
+ INT128, UINT128,
DBL, LDBL,
NOARG,
MAXSTATE
@@ -107,7 +110,7 @@ static const unsigned char states[]['z'-'A'+1] = {
union arg
{
- uintmax_t i;
+ uwide128 i;
long double f;
void *p;
};
@@ -116,21 +119,23 @@ static void pop_arg(union arg *arg, int type, va_list *ap)
{
switch (type) {
case PTR: arg->p = va_arg(*ap, void *);
- break; case INT: arg->i = va_arg(*ap, int);
- break; case UINT: arg->i = va_arg(*ap, unsigned int);
- break; case LONG: arg->i = va_arg(*ap, long);
- break; case ULONG: arg->i = va_arg(*ap, unsigned long);
- break; case ULLONG: arg->i = va_arg(*ap, unsigned long long);
- break; case SHORT: arg->i = (short)va_arg(*ap, int);
- break; case USHORT: arg->i = (unsigned short)va_arg(*ap, int);
- break; case CHAR: arg->i = (signed char)va_arg(*ap, int);
- break; case UCHAR: arg->i = (unsigned char)va_arg(*ap, int);
- break; case LLONG: arg->i = va_arg(*ap, long long);
- break; case SIZET: arg->i = va_arg(*ap, size_t);
- break; case IMAX: arg->i = va_arg(*ap, intmax_t);
- break; case UMAX: arg->i = va_arg(*ap, uintmax_t);
- break; case PDIFF: arg->i = va_arg(*ap, ptrdiff_t);
- break; case UIPTR: arg->i = (uintptr_t)va_arg(*ap, void *);
+ break; case INT: arg->i = __uwide128_i64(va_arg(*ap, int));
+ break; case UINT: arg->i = __uwide128_u64(va_arg(*ap, unsigned int));
+ break; case LONG: arg->i = __uwide128_i64(va_arg(*ap, long));
+ break; case ULONG: arg->i = __uwide128_u64(va_arg(*ap, unsigned long));
+ break; case ULLONG: arg->i = __uwide128_u64(va_arg(*ap, unsigned long long));
+ break; case SHORT: arg->i = __uwide128_i64((short)va_arg(*ap, int));
+ break; case USHORT: arg->i = __uwide128_u64((unsigned short)va_arg(*ap, int));
+ break; case CHAR: arg->i = __uwide128_i64((signed char)va_arg(*ap, int));
+ break; case UCHAR: arg->i = __uwide128_u64((unsigned char)va_arg(*ap, int));
+ break; case LLONG: arg->i = __uwide128_i64(va_arg(*ap, long long));
+ break; case SIZET: arg->i = __uwide128_u64(va_arg(*ap, size_t));
+ break; case IMAX: arg->i = __uwide128_i64(va_arg(*ap, intmax_t));
+ break; case UMAX: arg->i = __uwide128_u64(va_arg(*ap, uintmax_t));
+ break; case PDIFF: arg->i = __uwide128_i64(va_arg(*ap, ptrdiff_t));
+ break; case UIPTR: arg->i = __uwide128_u64((uintptr_t)va_arg(*ap, void *));
+ break; case INT128: arg->i = __uwide128_pop(ap);
+ break; case UINT128: arg->i = __uwide128_pop(ap);
break; case DBL: arg->f = va_arg(*ap, double);
break; case LDBL: arg->f = va_arg(*ap, long double);
}
@@ -213,7 +218,7 @@ static int wprintf_core(FILE *f, const wchar_t *fmt, va_list *ap, union arg *nl_
if (iswdigit(s[1]) && s[2]=='$') {
l10n=1;
nl_type[s[1]-'0'] = INT;
- w = nl_arg[s[1]-'0'].i;
+ w = nl_arg[s[1]-'0'].i.v64[lo64];
s+=3;
} else if (!l10n) {
w = f ? va_arg(*ap, int) : 0;
@@ -226,7 +231,7 @@ static int wprintf_core(FILE *f, const wchar_t *fmt, va_list *ap, union arg *nl_
if (*s=='.' && s[1]=='*') {
if (isdigit(s[2]) && s[3]=='$') {
nl_type[s[2]-'0'] = INT;
- p = nl_arg[s[2]-'0'].i;
+ p = nl_arg[s[2]-'0'].i.v64[lo64];
s+=4;
} else if (!l10n) {
p = f ? va_arg(*ap, int) : 0;
@@ -267,6 +272,7 @@ static int wprintf_core(FILE *f, const wchar_t *fmt, va_list *ap, union arg *nl_
#else
case 64: ps = LLPRE; st = (st == UINT) ? ULLONG : ((st == INT) ? LLONG : PTR); break;
#endif
+ case 128: ps = WWPRE; st = (st == UINT) ? UINT128 : ((st == INT) ? INT128 : PTR); break;
default: goto inval;
}
@@ -297,13 +303,14 @@ static int wprintf_core(FILE *f, const wchar_t *fmt, va_list *ap, union arg *nl_
case HHPRE: *(unsigned char *)arg.p = cnt; break;
case ZTPRE: *(size_t *)arg.p = cnt; break;
case JPRE: *(uintmax_t *)arg.p = cnt; break;
+ case WWPRE: *(uwide128 *)arg.p = __uwide128_i64(cnt); break;
}
continue;
case 'c':
case 'C':
if (w<1) w=1;
pad(f, w-1, fl);
- out(f, &(wchar_t){t=='C' ? arg.i : btowc(arg.i)}, 1);
+ out(f, &(wchar_t){t=='C' ? arg.i.v64[lo64] : btowc(arg.i.v64[lo64])}, 1);
pad(f, w-1, fl^LEFT_ADJ);
l = w;
continue;
--
2.34.1
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