[linuxsh-dev] floating point, C vs. CPP

[Pete L. <pet...@st...>]

Hi All,
Hopefully a quick question.
I'm compiling two files, one a C file and one a CPP file.  There is a single
function in both files, see below for the compilation flags and resulting
assembly.  It looks like the g++ compiler (3.0.3) ignores the -nofpu flag,
is this the expected behavior of the g++ compiler?
thanks for your time
- pete

void CFileUsingFloat(void)
{
	union{float f; int i;}tmpFloat;
	tmpFloat.f = sqrt(4.0);
}
sh4-linux-gcc -O2 -fno-rtti -fno-exceptions -fno-gnu-linker -Wstrict-prototy
pes -fomit-frame-pointer
-fno-strict-aliasing -pipe -fno-strength-reduce -D__KERNEL__ -DLINUX -D_LINU
X_COMP_ -D_PCI_DRIVER -ml -m4-nofpu -mno-implicit-fp -DCPU=sh4 -DMODULE -c -
o fp_testc.o fp_testc.c
000000e0 <CFileUsingFloat>:
      e0:	03 d1       	mov.l	f0 <CFileUsingFloat+0x10>,r1	! 0x0
      e2:	04 d5       	mov.l	f4 <CFileUsingFloat+0x14>,r5	! 0x40100000
      e4:	22 4f       	sts.l	pr,@-r15
      e6:	0b 41       	jsr	@r1
      e8:	00 e4       	mov	#0,r4
      ea:	26 4f       	lds.l	@r15+,pr
      ec:	0b 00       	rts
      ee:	09 00       	nop
      f0:	00 00       	.word 0x0000
      f2:	00 00       	.word 0x0000
      f4:	00 00       	.word 0x0000
      f6:	10 40       	dt	r0
      f8:	09 00       	nop
      fa:	09 00       	nop
      fc:	09 00       	nop
      fe:	09 00       	nop

void CPPFileUsingFloat(void)
{
	union{float f; int i;}tmpFloat;
	tmpFloat.f = sqrt(4.0);
}
sh4-linux-g++ -O2 -fno-rtti -fno-exceptions -fno-gnu-linker -Wstrict-prototy
pes -fomit-frame-pointer -fno-strict-aliasing -pipe -fno-strength-reduce -D_
_KERNEL__ -DLINUX -D_LINUX_COMP_ -D_PCI_DRIVER -ml -m4-nofpu -mno-implicit-f
p -DCPU=sh4 -c -o fp_testcpp.o fp_testcpp.cpp
000001c0 <CPPFileUsingFloat>:
     1c0:	04 d1       	mov.l	1d4 <CPPFileUsingFloat+0x14>,r1	! 0x0
     1c2:	22 4f       	sts.l	pr,@-r15
     1c4:	04 c7       	mova	1d8 <CPPFileUsingFloat+0x18>,r0
     1c6:	09 f5       	fmov	@r0+,fr5
     1c8:	0b 41       	jsr	@r1
     1ca:	09 f4       	fmov	@r0+,fr4
     1cc:	26 4f       	lds.l	@r15+,pr
     1ce:	0b 00       	rts
     1d0:	09 00       	nop
     1d2:	09 00       	nop
	...
     1dc:	00 00       	.word 0x0000
     1de:	10 40       	dt	r0