Re: [mpg123-devel] ARM cross compile

[Thomas O. <tho...@or...>]

Am Thu, 21 Jul 2011 20:14:42 +0800
schrieb JonY <jo...@us...>: 

> > using a command like this: ./configure
> > --target=arm-none-linux-gnueabi --host=arm-none-linuxgnueabi 
> > --prefix=/srv/nfs/poky/poky-image-minimal/igep002

> I'm not too clear on ARM asm myself, but --target= is for compilers and
> code generators, mpg123 doesn't generate code, so its superfluous.

Hm, but it should not hurt. One hint about the concerned ASM code, though. It's a macro defined in src/libmpg123/mpg123lib_intern.h, REAL_MUL_ASM():

#  elif defined(OPT_ARM)
/* for arm */
#   define REAL_MUL_ASM(x, y, radix) \
({ \
	long _x=(x), _y=(y), _mull, _mulh; \
	__asm__ ( \
		"smull %0, %1, %2, %3 \n\t" \
		"mov %0, %0, lsr %4 \n\t" \
		"orr %0, %0, %1, lsl %5 \n\t" \
		: "=&r" (_mull), "=&r" (_mulh) \
		: "%r" (_x), "r" (_y), "M" (radix), "M" (32-(radix)) \
	); \
	_mull; \
})

#   define REAL_MUL_SCALE_LAYER3_ASM(x, y, radix) \
({ \
	long _x=(x), _y=(y), _radix=(radix), _mull, _mulh, _radix2; \
	__asm__ ( \
		"smull %0, %1, %3, %4 \n\t" \
		"mov %0, %0, lsr %5 \n\t" \
		"rsb %2, %5, #32 \n\t" \
		"orr %0, %0, %1, lsl %2 \n\t" \
		: "=&r" (_mull), "=&r" (_mulh), "=&r" (_radix2) \
		: "%r" (_x), "r" (_y), "r" (_radix) \
	); \
	_mull; \
})
#  endif


The concerned one is the first of these two. You can try to get your build done by changing the

#  elif defined(OPT_ARM)

to

#  elif 0

to disable the definitions, prompting replacement C code. But it would be preferrable to fix this to make the optimized multiplication work again.

Anyhow, I second that:

> Which version of GCC are you using? Does compiling with -O0 work?

If -O0 works, this is a hint at a conflict of register usage bewteen the optimizer and the assembly code ... but then, the guy with the relevant experience on ARM assembly would be Taihei.


Alrighty then,

Thomas.