| /* |
| * x86_has_fpu.c |
| * |
| * Test for an x86 FPU, and do any necessary setup. |
| */ |
| |
| #if __SIZEOF_POINTER__ == 4 |
| #include <i386/x86_init_fpu.c> |
| #elif __SIZEOF_POINTER__ == 8 |
| #include <x86_64/x86_init_fpu.c> |
| #else |
| #error "Unable to build for to-be-defined architecture type" |
| #endif |
| #if 0 |
| #include <inttypes.h> |
| #include <sys/fpu.h> |
| |
| static inline uint64_t get_cr0(void) |
| { |
| #if __SIZEOF_POINTER__ == 4 |
| uint32_t v; |
| asm("movl %%cr0,%0":"=r"(v)); |
| #elif __SIZEOF_POINTER__ == 8 |
| uint64_t v; |
| asm("movq %%cr0,%0":"=r"(v)); |
| #else |
| #error "Unable to build for to-be-defined architecture type" |
| #endif |
| return v; |
| } |
| |
| static inline void set_cr0(uint32_t v) |
| { |
| #if __SIZEOF_POINTER__ == 4 |
| asm volatile ("movl %0,%%cr0"::"r" (v)); |
| #elif __SIZEOF_POINTER__ == 8 |
| asm volatile ("movq %0,%%cr0"::"r" ((uint64_t)v)); |
| #else |
| #error "Unable to build for to-be-defined architecture type" |
| #endif |
| } |
| |
| #define CR0_PE 0x00000001 |
| #define CR0_MP 0x00000002 |
| #define CR0_EM 0x00000004 |
| #define CR0_TS 0x00000008 |
| #define CR0_ET 0x00000010 |
| #define CR0_NE 0x00000020 |
| #define CR0_WP 0x00010000 |
| #define CR0_AM 0x00040000 |
| #define CR0_NW 0x20000000 |
| #define CR0_CD 0x40000000 |
| #define CR0_PG 0x80000000 |
| |
| int x86_init_fpu(void) |
| { |
| uint32_t cr0; |
| uint16_t fsw = 0xffff; |
| uint16_t fcw = 0xffff; |
| |
| cr0 = get_cr0(); |
| cr0 &= ~(CR0_EM | CR0_TS); |
| cr0 |= CR0_MP; |
| set_cr0(cr0); |
| |
| asm volatile ("fninit"); |
| asm volatile ("fnstsw %0":"+m" (fsw)); |
| if (fsw != 0) |
| return -1; |
| |
| asm volatile ("fnstcw %0":"+m" (fcw)); |
| if ((fcw & 0x103f) != 0x3f) |
| return -1; |
| |
| /* Techically, this could be a 386 with a 287. We could add a check |
| for that here... */ |
| |
| return 0; |
| } |
| #endif |