diff options
Diffstat (limited to 'grub-core/efiemu/i386/coredetect.c')
-rw-r--r-- | grub-core/efiemu/i386/coredetect.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/grub-core/efiemu/i386/coredetect.c b/grub-core/efiemu/i386/coredetect.c new file mode 100644 index 0000000..975c4aa --- /dev/null +++ b/grub-core/efiemu/i386/coredetect.c @@ -0,0 +1,59 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2009 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/efiemu/efiemu.h> +#include <grub/command.h> + +#define cpuid(num,a,b,c,d) \ + asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \ + : "=a" (a), "=r" (b), "=c" (c), "=d" (d) \ + : "0" (num)) + +#define bit_LM (1 << 29) + +char * +grub_efiemu_get_default_core_name (void) +{ + + unsigned int eax, ebx, ecx, edx; + unsigned int max_level; + unsigned int ext_level; + + /* See if we can use cpuid. */ + asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;" + "pushl %0; popfl; pushfl; popl %0; popfl" + : "=&r" (eax), "=&r" (ebx) + : "i" (0x00200000)); + if (((eax ^ ebx) & 0x00200000) == 0) + return "efiemu32.o"; + + /* Check the highest input value for eax. */ + cpuid (0, eax, ebx, ecx, edx); + /* We only look at the first four characters. */ + max_level = eax; + if (max_level == 0) + return "efiemu32.o"; + + cpuid (0x80000000, eax, ebx, ecx, edx); + ext_level = eax; + if (ext_level < 0x80000000) + return "efiemu32.o"; + + cpuid (0x80000001, eax, ebx, ecx, edx); + return (edx & bit_LM) ? "efiemu64.o" : "efiemu32.o"; +} |