diff options
Diffstat (limited to 'code16.c')
| -rw-r--r-- | code16.c | 23 |
1 files changed, 16 insertions, 7 deletions
@@ -1,4 +1,5 @@ asm(".code16gcc"); +#include <stddef.h> #include "bios.h" #include "segment.h" #include "ioport.h" @@ -23,32 +24,40 @@ static inline uint32_t rdfs32(unsigned long addr) { uint32_t v; - asm volatile("addr32 movl %%fs:%1,%0" : "=q" (v) : "m" (*(uint32_t *)addr)); + asm volatile("addr32 movl %%fs:%1,%0" : "=r" (v) : "m" (*(uint32_t *)addr)); return v; } -struct e820map e820; +static inline uint16_t rdcs16(void *p) +{ + uint32_t addr = ((uintptr_t) p) & 65535; + uint16_t v; + + asm volatile("addr32 movw %%cs:%1,%0" : "=r" (v) : "m" (*(uint32_t *)addr)); + + return v; +} + +uint16_t e820_seg; bioscall void e820_query_map(struct biosregs *regs) { uint32_t map_size; - uint16_t fs_seg; uint32_t ndx; - fs_seg = flat_to_seg16((uintptr_t) &e820); - set_fs(fs_seg); + set_fs(rdcs16(&e820_seg)); ndx = regs->ebx; - map_size = rdfs32(flat_to_off16((uintptr_t) &e820.nr_map)); + map_size = rdfs32(offsetof(struct e820map, nr_map)); if (ndx < map_size) { uint32_t start; unsigned int i; uint8_t *p; - start = flat_to_off16((uintptr_t)&e820.map[ndx]); + start = flat_to_off16(offsetof(struct e820map, map[ndx])); p = (void *) regs->edi; |