ref: 49bd8a86f3a07c4f54df94838c07fa653d725afa
dir: /sys/src/9/pc/bios32.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "io.h" #define VFLAG(...) if(vflag) print(__VA_ARGS__) #define UPTR2INT(p) ((uintptr)(p)) #define l16get(p) (((p)[1]<<8)|(p)[0]) #define l32get(p) (((u32int)l16get(p+2)<<16)|l16get(p)) static int vflag = 0; typedef struct BIOS32sdh { /* BIOS32 Service Directory Header */ u8int signature[4]; /* "_32_" */ u8int physaddr[4]; /* physical address of entry point */ u8int revision; u8int length; /* of header in paragraphs */ u8int checksum; /* */ u8int reserved[5]; } BIOS32sdh; typedef struct BIOS32si { /* BIOS32 Service Interface */ u8int* base; /* base address of service */ int length; /* length of service */ u32int offset; /* service entry-point from base */ u16int ptr[3]; /* far pointer m16:32 */ } BIOS32si; static Lock bios32lock; static u16int bios32ptr[3]; static void* bios32entry; int bios32ci(BIOS32si* si, BIOS32ci* ci) { int r; lock(&bios32lock); r = bios32call(ci, si->ptr); unlock(&bios32lock); return r; } static int bios32locate(void) { uintptr ptr; BIOS32sdh *sdh; VFLAG("bios32link\n"); if((sdh = sigsearch("_32_", sizeof(BIOS32sdh))) == nil) return -1; VFLAG("sdh @ %#p, entry %#ux\n", sdh, l32get(sdh->physaddr)); bios32entry = vmap(l32get(sdh->physaddr), 4096+1); VFLAG("entry @ %#p\n", bios32entry); ptr = UPTR2INT(bios32entry); bios32ptr[0] = ptr & 0xffff; bios32ptr[1] = (ptr>>16) & 0xffff; bios32ptr[2] = KESEL; VFLAG("bios32link: ptr %ux %ux %ux\n", bios32ptr[0], bios32ptr[1], bios32ptr[2]); return 0; } void BIOS32close(BIOS32si* si) { vunmap(si->base, si->length); free(si); } BIOS32si* bios32open(char* id) { uint ptr; BIOS32ci ci; BIOS32si *si; lock(&bios32lock); if(bios32ptr[2] == 0 && bios32locate() < 0){ unlock(&bios32lock); return nil; } VFLAG("bios32si: %s\n", id); memset(&ci, 0, sizeof(BIOS32ci)); ci.eax = (id[3]<<24|(id[2]<<16)|(id[1]<<8)|id[0]); bios32call(&ci, bios32ptr); unlock(&bios32lock); VFLAG("bios32si: eax %ux\n", ci.eax); if(ci.eax & 0xff) return nil; VFLAG("bios32si: base %#ux length %#ux offset %#ux\n", ci.ebx, ci.ecx, ci.edx); if((si = malloc(sizeof(BIOS32si))) == nil) return nil; if((si->base = vmap(ci.ebx, ci.ecx)) == nil){ free(si); return nil; } si->length = ci.ecx; ptr = UPTR2INT(si->base)+ci.edx; si->ptr[0] = ptr & 0xffff; si->ptr[1] = (ptr>>16) & 0xffff; si->ptr[2] = KESEL; VFLAG("bios32si: eax entry %ux\n", ptr); return si; }