On Fri, Jun 21, 2013 at 10:20:01AM +0200, Mark Kettenis wrote:
> > Date: Fri, 21 Jun 2013 17:31:39 +1000
> > From: Jonathan Gray <[email protected]>
> >
> > Both gcc and clang have an extension for binary integer constants.
> > In gcc's case this has been around since 4.3.
> >
> > The mesa backend for newer intel parts (i965) assumes this extension
> > is present in recent versions.
>
> Sigh... Can't these people just write portable C?
>
> > Below is a diff to add support for this to our in tree gcc4. While the
> > i965 backend is only built on gcc4 archs the concern is that abuse
> > of this extension in ports or other places may make gcc3/gcc2 archs
> > worse off unless similiar patches can be done...
>
> Well, lots of ports stuff is compiled with newer gcc versions anyway.
>
> Looks like it is trivial to bring this extension to gcc3, since the
> code seems to be almost unchanged in gcc4. It just moved to a
> different location.
Here is the gcc3 diff:
Index: gcc/cppexp.c
===================================================================
RCS file: /cvs/src/gnu/usr.bin/gcc/gcc/cppexp.c,v
retrieving revision 1.1.1.1
diff -u -p -r1.1.1.1 cppexp.c
--- gcc/cppexp.c 29 Nov 2003 12:21:45 -0000 1.1.1.1
+++ gcc/cppexp.c 26 Jun 2013 03:17:21 -0000
@@ -178,6 +178,11 @@ cpp_classify_number (pfile, token)
radix = 16;
str++;
}
+ else if ((*str == 'b' || *str == 'B') && (str[1] == '0' || str[1] ==
'1'))
+ {
+ radix = 2;
+ str++;
+ }
}
/* Now scan for a well-formed integer or float. */
@@ -216,10 +221,22 @@ cpp_classify_number (pfile, token)
radix = 10;
if (max_digit >= radix)
- SYNTAX_ERROR2 ("invalid digit \"%c\" in octal constant", '0' + max_digit);
+ {
+ if (radix == 2)
+ SYNTAX_ERROR2 ("invalid digit \"%c\" in binary constant", '0' +
max_digit);
+ else
+ SYNTAX_ERROR2 ("invalid digit \"%c\" in octal constant", '0' +
max_digit);
+ }
if (float_flag != NOT_FLOAT)
{
+ if (radix == 2)
+ {
+ cpp_error (pfile, DL_ERROR,
+ "invalid prefix \"0b\" for floating constant");
+ return CPP_N_INVALID;
+ }
+
if (radix == 16 && CPP_PEDANTIC (pfile) && !CPP_OPTION (pfile, c99))
cpp_error (pfile, DL_PEDWARN,
"use of C99 hexadecimal floating constant");
@@ -293,11 +310,15 @@ cpp_classify_number (pfile, token)
if ((result & CPP_N_IMAGINARY) && CPP_PEDANTIC (pfile))
cpp_error (pfile, DL_PEDWARN, "imaginary constants are a GCC extension");
+ if (radix == 2 && CPP_PEDANTIC (pfile))
+ cpp_error (pfile, DL_PEDWARN, "binary constants are a GCC extension");
if (radix == 10)
result |= CPP_N_DECIMAL;
else if (radix == 16)
result |= CPP_N_HEX;
+ else if (radix == 2)
+ result |= CPP_N_BINARY;
else
result |= CPP_N_OCTAL;
@@ -350,6 +371,11 @@ cpp_interpret_integer (pfile, token, typ
base = 16;
p += 2;
}
+ else if ((type & CPP_N_RADIX) == CPP_N_BINARY)
+ {
+ base = 2;
+ p += 2;
+ }
/* We can add a digit to numbers strictly less than this without
needing the precision and slowness of double integers. */
@@ -409,12 +435,25 @@ append_digit (num, digit, base, precisio
size_t precision;
{
cpp_num result;
- unsigned int shift = 3 + (base == 16);
+ unsigned int shift;
bool overflow;
cpp_num_part add_high, add_low;
- /* Multiply by 8 or 16. Catching this overflow here means we don't
+ /* Multiply by 2, 8 or 16. Catching this overflow here means we don't
need to worry about add_high overflowing. */
+ switch (base)
+ {
+ case 2:
+ shift = 1;
+ break;
+
+ case 16:
+ shift = 4;
+ break;
+
+ default:
+ shift = 3;
+ }
overflow = !!(num.high >> (PART_PRECISION - shift));
result.high = num.high << shift;
result.low = num.low << shift;
Index: gcc/cpplib.h
===================================================================
RCS file: /cvs/src/gnu/usr.bin/gcc/gcc/cpplib.h,v
retrieving revision 1.1.1.2
diff -u -p -r1.1.1.2 cpplib.h
--- gcc/cpplib.h 24 Dec 2004 23:51:31 -0000 1.1.1.2
+++ gcc/cpplib.h 26 Jun 2013 03:10:33 -0000
@@ -630,6 +630,7 @@ struct cpp_num
#define CPP_N_DECIMAL 0x0100
#define CPP_N_HEX 0x0200
#define CPP_N_OCTAL 0x0400
+#define CPP_N_BINARY 0x0800
#define CPP_N_UNSIGNED 0x1000 /* Properties. */
#define CPP_N_IMAGINARY 0x2000
