diff options
Diffstat (limited to 'src/arch/i386')
-rw-r--r-- | src/arch/i386/include/div64.h | 48 | ||||
-rw-r--r-- | src/arch/i386/smp/mpspec.c | 2 |
2 files changed, 49 insertions, 1 deletions
diff --git a/src/arch/i386/include/div64.h b/src/arch/i386/include/div64.h new file mode 100644 index 0000000000..28ed8b296a --- /dev/null +++ b/src/arch/i386/include/div64.h @@ -0,0 +1,48 @@ +#ifndef __I386_DIV64 +#define __I386_DIV64 + +/* + * do_div() is NOT a C function. It wants to return + * two values (the quotient and the remainder), but + * since that doesn't work very well in C, what it + * does is: + * + * - modifies the 64-bit dividend _in_place_ + * - returns the 32-bit remainder + * + * This ends up being the most efficient "calling + * convention" on x86. + */ +#define do_div(n,base) ({ \ + unsigned long __upper, __low, __high, __mod, __base; \ + __base = (base); \ + asm("":"=a" (__low), "=d" (__high):"A" (n)); \ + __upper = __high; \ + if (__high) { \ + __upper = __high % (__base); \ + __high = __high / (__base); \ + } \ + asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \ + asm("":"=A" (n):"a" (__low),"d" (__high)); \ + __mod; \ +}) + +/* + * (long)X = ((long long)divs) / (long)div + * (long)rem = ((long long)divs) % (long)div + * + * Warning, this will do an exception if X overflows. + */ +#define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c) + +extern inline long +div_ll_X_l_rem(long long divs, long div, long *rem) +{ + long dum2; + __asm__("divl %2":"=a"(dum2), "=d"(*rem) + : "rm"(div), "A"(divs)); + + return dum2; + +} +#endif diff --git a/src/arch/i386/smp/mpspec.c b/src/arch/i386/smp/mpspec.c index c674cf58f5..daeb78435d 100644 --- a/src/arch/i386/smp/mpspec.c +++ b/src/arch/i386/smp/mpspec.c @@ -121,7 +121,7 @@ void smp_write_processors(struct mp_config_table *mc) } cpu_flag = MPC_CPU_ENABLED; if (boot_apic_id == cpu->path.u.apic.apic_id) { - cpu_flag = MPC_CPU_ENABLED; + cpu_flag = MPC_CPU_ENABLED | MPC_CPU_BOOTPROCESSOR; } smp_write_processor(mc, cpu->path.u.apic.apic_id, apic_version, |