diff options
-rw-r--r-- | lib/libc/i386/gen/fixunsdfsi.S | 59 |
1 files changed, 22 insertions, 37 deletions
diff --git a/lib/libc/i386/gen/fixunsdfsi.S b/lib/libc/i386/gen/fixunsdfsi.S index f61daee..cf58b28 100644 --- a/lib/libc/i386/gen/fixunsdfsi.S +++ b/lib/libc/i386/gen/fixunsdfsi.S @@ -34,49 +34,34 @@ * SUCH DAMAGE. * * from: @(#)fixunsdfsi.s 5.1 12/17/90 - * $Id: fixunsdfsi.S,v 1.1 1993/12/05 13:01:03 ats Exp $ + * $Id: fixunsdfsi.S,v 1.1 1994/08/05 01:18:05 wollman Exp $ */ -#if defined(LIBC_SCCS) - .text - .asciz "$Id: fixunsdfsi.S,v 1.1 1993/12/05 13:01:03 ats Exp $" -#endif +#if defined(LIBC_SCCS) && !defined(lint) + .asciz "$Id: fixunsdfsi.S,v 1.1 1994/08/05 01:18:05 wollman Exp $" +#endif /* LIBC_SCCS and not lint */ #include "DEFS.h" -#include "SYS.h" ENTRY(__fixunsdfsi) - fldl 4(%esp) /* argument double to accum stack */ - frndint /* create integer */ -#ifdef PIC - PIC_PROLOGUE - leal PIC_GOTOFF(fbiggestsigned),%eax - PIC_EPILOGUE - fcoml (%eax) -#else - fcoml PIC_GOTOFF(fbiggestsigned) /* bigger than biggest signed? */ -#endif - fstsw %ax - sahf - jnb 1f - - fistpl 4(%esp) + fldl 4(%esp) + fnstcw 4(%esp) movl 4(%esp),%eax + orb $(3 << 2),%ah # change rounding mode bitfield to 3 (chop) + movl %eax,8(%esp) + fldcw 8(%esp) + subl $8,%esp + fistpq (%esp) # convert to 64 bit integer + popl %eax + popl %edx # discard top 32 bits + fldcw 4(%esp) ret -1: -#ifdef PIC - PIC_PROLOGUE - leal PIC_GOTOFF(fbiggestsigned),%eax - PIC_EPILOGUE - fsubl (%eax) -#else - fsubl PIC_GOTOFF(fbiggestsigned) /* reduce for proper conversion */ -#endif - fistpl 4(%esp) /* convert */ - movl 4(%esp),%eax - orl $0x80000000,%eax /* restore bias */ - PIC_EPILOGUE - ret - -fbiggestsigned: .double 0r2147483648.0 +/* + * XXX - we are sloppy about overflow, the same as gcc-2. Values too big + * for a 64-bit (signed) integer cause an overflow trap or are silently + * converted to 0 if the overflow trap is masked. The remaining values + * too big for a 32-bit (unsigned) integer are silently truncated to 32 + * bits. Negative values are converted like negative ints (no overflow) + * if they fit in 32 bits. + */ |