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DOS: XMS setup initializes the proper size for UMB region, do not re-initialize again. This fixes problems in PC-98 mode where booting a guest OS unmaps the UMB region AND the PC-98 SOUND ROM BIOS (overlap)

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Jonathan Campbell
2018-11-18 07:22:57 -08:00
parent fe2b188022
commit 066e80f599
1 changed files with 4 additions and 0 deletions
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4
src/dos/dos_memory.cpp
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@@ -419,6 +419,9 @@ void DOS_BuildUMBChain(bool umb_active,bool ems_active) {
/* UMBs are only possible if the machine has 1MB+64KB of RAM */
if (umb_active && (machine!=MCH_TANDY) && seg_limit >= (0x10000+0x1000-1) && first_umb_seg < GetEMSPageFrameSegment()) {
/* XMS emulation sets UMB size now.
* PCjr mode disables UMB emulation */
#if 0
if (ems_active) {
/* we can use UMBs up to the EMS page frame */
/* FIXME: when we make the EMS page frame configurable this will need to be updated */
@@ -428,6 +431,7 @@ void DOS_BuildUMBChain(bool umb_active,bool ems_active) {
/* we can use UMBs up to where PCjr wants cartridge ROM */
first_umb_size = 0xE000 - first_umb_seg;
}
#endif
dos_infoblock.SetStartOfUMBChain(UMB_START_SEG);
dos_infoblock.SetUMBChainState(0); // UMBs not linked yet