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Fixed reading extended memory size from CMOS.

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This commit is contained in:
Volker Ruppert 2017-02-11 08:53:00 +00:00
parent 72b2de2799
commit f2abe7c033
1 changed files with 9 additions and 10 deletions
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19
bochs/bios/rombios.c
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@ -4639,26 +4639,25 @@ ASM_END
case 0xe8:
switch(regs.u.r8.al) {
case 0x20: // coded by osmaker aka K.J.
if(regs.u.r32.edx == 0x534D4150)
{
LOBYTE(extended_memory_size) = inb_cmos(0x35);
HIBYTE(LOWORD(extended_memory_size)) = inb_cmos(0x34);
if (regs.u.r32.edx == 0x534D4150) {
LOBYTE(extended_memory_size) = inb_cmos(0x34);
HIBYTE(LOWORD(extended_memory_size)) = inb_cmos(0x35);
extended_memory_size *= 64;
if(extended_memory_size > 0x2fc000) {
if (extended_memory_size > 0x2fc000) {
extended_memory_size = 0x2fc000; // everything after this is reserved memory until we get to 0x100000000
}
extended_memory_size *= 1024;
extended_memory_size += (16L * 1024 * 1024);
if(extended_memory_size <= (16L * 1024 * 1024)) {
LOBYTE(extended_memory_size) = inb_cmos(0x31);
HIBYTE(LOWORD(extended_memory_size)) = inb_cmos(0x30);
if (extended_memory_size <= (16L * 1024 * 1024)) {
LOBYTE(extended_memory_size) = inb_cmos(0x30);
HIBYTE(LOWORD(extended_memory_size)) = inb_cmos(0x31);
extended_memory_size *= 1024;
extended_memory_size += (1L * 1024 * 1024);
}
LOBYTE(HIWORD(extra_lowbits_memory_size)) = inb_cmos(0x5c);
HIBYTE(HIWORD(extra_lowbits_memory_size)) = inb_cmos(0x5b);
LOBYTE(HIWORD(extra_lowbits_memory_size)) = inb_cmos(0x5b);
HIBYTE(HIWORD(extra_lowbits_memory_size)) = inb_cmos(0x5c);
LOWORD(extra_lowbits_memory_size) = 0;
extra_highbits_memory_size = inb_cmos(0x5d);