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m68k: handle presence of 64bit mul/div instructions cleanly

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The traditional 68000 processors and the newer reduced instruction set
ColdFire processors do not support the 32*32->64 multiply or the 64/32->32
divide instructions. This is not a difference based on the presence of
a hardware MMU or not.

Create a new config symbol to mark that a CPU type doesn't support the
longer multiply/divide instructions. Use this then as a basis for using
the fast 64bit based divide (in div64.h) and for linking in the extra
libgcc functions that may be required (mulsi3, divsi3, etc).

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Greg Ungerer
2011-11-11 15:13:08 +10:00
parent 7f73bafc46
commit 84f3fb7a2a
5 changed files with 13 additions and 10 deletions
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2
arch/m68k/kernel/m68k_ksyms.c
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@@ -14,7 +14,7 @@ EXPORT_SYMBOL(__ashrdi3);
EXPORT_SYMBOL(__lshrdi3);
EXPORT_SYMBOL(__muldi3);
#if defined(CONFIG_M68000) || defined(CONFIG_COLDFIRE)
#if defined(CONFIG_CPU_HAS_NO_MULDIV64)
/*
* Simpler 68k and ColdFire parts also need a few other gcc functions.
*/