Re: problem with crosstool 0.28-pre28 supplied patch for gcc 3.3.[23] softfloat on ARM

[Lennert Buytenhek <buytenh at wantstofly dot org>]

On Mon, Aug 16, 2004 at 02:23:54AM +0200, Dimitry Andric wrote:

> I suppose this is what crosstool's patches/glibc-2.3.2/glibc-vfp.patch
> should fix.  Are you sure it is applied correctly?  It seems that
> glibc interprets the float endianness incorrectly, thus printing
> garbage.

OK, I think the kernel does it okay, at least for multiplies, because
I see this:

% cat x.c                                                                  /tmp
#include <stdio.h>
#include <stdlib.h>

void dumpfloat(float x)
{
        printf("%.8x\n", *((unsigned int *)&x));
}

int main()
{
        volatile float x;

        x = 6.66;
        dumpfloat(x * x);
        dumpfloat(6.66 * 6.66);

        return 0;
}


Source snippet:

main:
        @ args = 0, pretend = 0, frame = 4
        @ frame_needed = 1, uses_anonymous_args = 0
        mov     ip, sp
        stmfd   sp!, {fp, ip, lr, pc}
        sub     fp, ip, #4
        sub     sp, sp, #4
        ldr     r3, .L5 @ float
        str     r3, [fp, #-16]  @ float
        ldfs    f1, [fp, #-16]
        ldfs    f0, [fp, #-16]
        fmls    f0, f1, f0
        stfs    f0, [sp, #-4]!
        ldr     r0, [sp], #4
        bl      dumpfloat
        ldr     r0, .L5+4
        bl      printf
        ldr     r0, .L5+8       @ float
        bl      dumpfloat
        ldr     r0, .L5+4
        bl      printf
        mov     r3, #0
        mov     r0, r3
        ldmfd   sp, {r3, fp, sp, pc}
.L6:
        .align  2
.L5:
        .word   1087708856
        .word   .LC1
        .word   1110535202
        .size   main, .-main
        .ident  "GCC: (GNU) 3.4.1"



Output on target:
[root@enp2611 tmp]# ./x
42316c22
42316c22
[root@enp2611 tmp]# 


cheers,
Lennert

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