Kevin D. Kissell writes:
>
> From: "Hartvig Ekner" <hartvige@mips.com>
> To: "user alias" <linux-mips@oss.sgi.com>
> > > From: "Kevin D. Kissell" <kevink@mips.com>
> > > To: <linux-mips@fnet.fr>, <linux-mips@oss.sgi.com>
> > > Subject: Linux and the Sony Playstation 2
> > > Date: Tue, 18 Jun 2002 15:59:57 +0200
> > >
> > > The Sony PS2 Linux kit has been shipping for nearly
> > > a month now, and I'm frankly astonished at how little
> > > I've seen on this mailing list about it. For better or
> > > for worse, this changes everything for MIPS/Linux.
> > > The number of MIPS/Linux users worldwide has
> > > just gone up by at least an order of magnitude,
> > > and they are on a platform running a 2.2.1-derived
> > > kernel and using gcc 2.95.2.
> > >
> > > It's a perfectly usable platform out of the box, but
> > > Carsten has thrown "crashme" at it, and it goes down
> > > relatively quickly. People trying to port kaffe and
> > > other programs that do double-precision float are
> > > blocked because there's no double precision on the
> > > R5900, and the Sony kernel lacks the Algorithmics
> > > emulator.
> >
> > The few simple double-precision programs (ala hello world) I ran worked,
> > and the compiler substitutes integer code (softfloat) for any double
> > precision operation. What are the things known not to work?
>
> You didn't disassemble the code. The Sony gcc distribution
> is hard-wired to generate soft-float code, even if you
> specify -mhard-float on the command line.
I did disassemble the code. It generates true FPU code for floats, and
soft-float for double. See the example below:
[hartvige@copps01 test]$ more hellof.c
int main()
{
float a,b;
a = 3.0f;
b = a + 2.0f;
printf("hello world %f\n",b);
}
gcc hellof.c, and disassembling:
0000000000400a70 <main>:
400a70: 3c1c0fc0 lui $gp,0xfc0
400a74: 279c75c0 addiu $gp,$gp,30144
400a78: 0399e021 addu $gp,$gp,$t9
400a7c: 27bdffc0 addiu $sp,$sp,-64
400a80: afbc0010 sw $gp,16($sp)
400a84: afbf0038 sw $ra,56($sp)
400a88: afbe0034 sw $s8,52($sp)
400a8c: afbc0030 sw $gp,48($sp)
400a90: 03a0f021 move $s8,$sp
400a94: 3c014040 lui $at,0x4040
400a98: 44810000 mtc1 $at,$f0
400a9c: 00000000 nop
400aa0: e7c00020 swc1 $f0,32($s8)
400aa4: c7c00020 lwc1 $f0,32($s8)
400aa8: 3c014000 lui $at,0x4000
400aac: 44810800 mtc1 $at,$f1
400ab0: 00000000 nop
400ab4: 46010000 add.s $f0,$f0,$f1
400ab8: e7c00024 swc1 $f0,36($s8)
400abc: c7cc0024 lwc1 $f12,36($s8)
400ac0: 8f998054 lw $t9,-32684($gp)
400ac4: 0320f809 jalr $t9
400ac8: 00000000 nop
400acc: 8fdc0010 lw $gp,16($s8)
400ad0: 8f848018 lw $a0,-32744($gp)
400ad4: 24841040 addiu $a0,$a0,4160
400ad8: 00403021 move $a2,$v0
400adc: 00603821 move $a3,$v1
400ae0: 8f998064 lw $t9,-32668($gp)
400ae4: 0320f809 jalr $t9
400ae8: 00000000 nop
400aec: 8fdc0010 lw $gp,16($s8)
400af0: 03c0e821 move $sp,$s8
Were you talking about double-precision only, or is there something different
in the kits?
/Hartvig
