Re: [PATCH] Compile failure fix for ppc on 2.6.17-rc4-mm3 (2nd attempt)

From: Segher Boessenkool
Date: Mon May 29 2006 - 12:21:39 EST


arch/powerpc/kernel/built-in.o(.init.text+0x77b4): In function `vrsqrtefp':
: undefined reference to `__udivdi3'
arch/powerpc/kernel/built-in.o(.init.text+0x7800): In function `vrsqrtefp':
: undefined reference to `__udivdi3'
make: *** [.tmp_vmlinux1] Error 1

A function with a name like that doesn't _deserve_ to compile.

Would vector_reciprocal_square_root_estimate_floating_point() be any better...
Anyway, this is just a machine insn mnemonic, so the function name is fine
I believe.

#define push_end(res, size) do { unsigned long __sz = (size) ; \
- res->end = ((res->end + __sz) / (__sz + 1)) * (__sz + 1) + __sz; \
+ resource_size_t farEnd = (res->end + __sz); \
+ do_div(farEnd, (__sz + 1)); \
+ res->end = farEnd * (__sz + 1) + __sz; \
} while (0)

Size here is a) a misnomer (size + 1 is the actual size) and b) always a power
of two minus one. So instead, do

#define push_end(res, mask) res->end = -(-res->end & ~(unsigned long)mask)

(with a do { } while(0) armour if you prefer).


Segher

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