[Bug target/19571] floating point registers not preserved during function call

[rearnsha at gcc dot gnu dot org]

------- Additional Comments From rearnsha at gcc dot gnu dot org  2005-01-22 10:36 -------
The code generated looks correct to me.

The generated assembler that you've give for __cos is clearly saving and
restoring f4-f7.
__cos:
// Saves the integer registers
    ca4c:	e92d4070 	stmdb	sp!, {r4, r5, r6, lr}
// Does some processing that does not involve floating point
    ca50:	e3c02102 	bic	r2, r0, #-2147483648	; 0x80000000
    ca54:	e35205f9 	cmp	r2, #1044381696	; 0x3e400000
    ca58:	e1a05001 	mov	r5, r1
    ca5c:	e1a04000 	mov	r4, r0
// Sets f0: OK, since f0 is call-clobbered.
    ca60:	be008189 	mvfltd	f0, #1.0
// This instruction saves 4 floating point registers, starting with f4 on the stack
    ca64:	ed2d420c 	sfm	f4, 4, [sp, #-48]!

... // Rest of function

// And this instruction loads them back again.
    ccec:	ecbd420c 	lfm	f4, 4, [sp], #48
    ccf0:	e8bd8070 	ldmia	sp!, {r4, r5, r6, pc}

As far as I can see this is the only exit point from the generated code.

I think you need to check that the floating point emulator in your kernel is
functioning correctly.  Particularly for lfm/sfm.

R.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19571