// Search for the MP Floating Pointer Structure, which according to
// [MP 4] is in one of the following three locations:
// 1) in the first KB of the EBDA;
// 2) if there is no EBDA, in the last KB of system base memory;
// 3) in the BIOS ROM between 0xE0000 and 0xFFFFF.
static struct mp *
mpsearch(void)
{
uint8_t *bda;
uint32_t p;
struct mp *mp;
static_assert(sizeof(*mp) == 16);
// The BIOS data area lives in 16-bit segment 0x40.
bda = (uint8_t *) KADDR(0x40 << 4);
// [MP 4] The 16-bit segment of the EBDA is in the two bytes
// starting at byte 0x0E of the BDA. 0 if not present.
if ((p = *(uint16_t *) (bda + 0x0E))) {
p <<= 4; // Translate from segment to PA
if ((mp = mpsearch1(p, 1024)))
return mp;
} else {
// The size of base memory, in KB is in the two bytes
// starting at 0x13 of the BDA.
p = *(uint16_t *) (bda + 0x13) * 1024;
if ((mp = mpsearch1(p - 1024, 1024)))
return mp;
}
return mpsearch1(0xF0000, 0x10000);
}
// Search for the MP Floating Pointer Structure, which according to the
// spec is in one of the following three locations:
// 1) in the first KB of the EBDA;
// 2) in the last KB of system base memory;
// 3) in the BIOS ROM between 0xE0000 and 0xFFFFF.
static struct mp*
mpsearch(void)
{
uchar *bda;
uint p;
struct mp *mp;
bda = (uchar *) P2V(0x400);
if((p = ((bda[0x0F]<<8)| bda[0x0E]) << 4)){
if((mp = mpsearch1(p, 1024)))
return mp;
} else {
p = ((bda[0x14]<<8)|bda[0x13])*1024;
if((mp = mpsearch1(p-1024, 1024)))
return mp;
}
return mpsearch1(0xF0000, 0x10000);
}
// Search for the MP Floating Pointer Structure, which according to the
// spec is in one of the following three locations:
// 1) in the first KB of the EBDA;
// 2) in the last KB of system base memory;
// 3) in the BIOS ROM between 0xE0000 and 0xFFFFF.
static struct mp *
mpsearch(void)
{
uint8_t *bda;
uintptr_t p;
struct mp *mp;
bda = (uint8_t *) 0x400;
if ((p = ((bda[0x0F] << 8) | bda[0x0E]) << 4)) {
if ((mp = mpsearch1((uint8_t *) p, 1024)))
return mp;
} else {
p = ((bda[0x14] << 8) | bda[0x13]) * 1024;
if ((mp = mpsearch1((uint8_t *) p - 1024, 1024)))
return mp;
}
return mpsearch1((uint8_t *) 0xF0000, 0x10000);
}
