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Simplifies banks $02+ to a single region.

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Thomas Harte 2021-02-27 23:34:51 -05:00
parent 267e28e012
commit 8604b1786e
1 changed files with 6 additions and 38 deletions
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44
Machines/Apple/AppleIIgs/MemoryMap.hpp
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@ -130,32 +130,11 @@ class MemoryMap {
0xffff
});
// Banks $02–[end of RAM]: all locations potentially affected by shadowing.
const uint8_t fast_ram_bank_count = uint8_t((ram.size() - 0x02'0000) / 0x01'0000);
if(fast_ram_bank_count > 2) {
const std::vector<uint8_t> evens = {
region(), // 0x0000 – 0x0400.
region(), // 0x0400 – 0x0800.
region(), // 0x0800 – 0x0c00.
region(), // 0x0c00 – 0x2000.
region(), // 0x2000 – 0x4000.
region(), // 0x4000 – 0x6000.
region(), // 0x6000 – [end].
};
const std::vector<uint8_t> odds = {
region(), // 0x0000 – 0x0400.
region(), // 0x0400 – 0x0800.
region(), // 0x0800 – 0x0c00.
region(), // 0x0c00 – 0x2000.
region(), // 0x2000 – 0x4000.
region(), // 0x4000 – 0x6000.
region(), // 0x6000 – 0xa000.
region(), // 0xa000 – [end].
};
for(uint8_t bank = 0x02; bank < fast_ram_bank_count; bank += 2) {
set_regions(bank, {0x0400, 0x0800, 0x0c00, 0x2000, 0x4000, 0x6000, 0xffff}, evens);
set_regions(bank+1, {0x0400, 0x0800, 0x0c00, 0x2000, 0x4000, 0x6000, 0xa000, 0xffff}, odds);
}
// Banks $02–[end of RAM]: a single region.
const auto fast_region = region();
const uint8_t fast_ram_bank_limit = uint8_t(ram.size() / 0x01'0000);
for(uint8_t bank = 0x02; bank < fast_ram_bank_limit; bank++) {
set_region(bank, 0x0000, 0xffff, fast_region);
}
// [Banks $80–$e0: empty].
@ -430,15 +409,6 @@ class MemoryMap {
//
// Completely distinct from the auxiliary and language card switches.
void set_shadowing() {
// Disables shadowing for the region starting from @c zone if @c flag is true;
// otherwise enables it.
#define apply(disable, zone) \
if(disable) { \
regions[region_map[zone]].flags &= ~Region::IsShadowed; \
} else { \
regions[region_map[zone]].flags |= Region::IsShadowed; \
}
// Relevant bits:
//
// b5: inhibit shadowing, text page 2 [if ROM 03; as if always set otherwise]
@ -492,8 +462,6 @@ class MemoryMap {
for(size_t c = 0x6000 >> shadow_shift; c < 0xa000 >> shadow_shift; c++) {
is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x08);
}
#undef apply
}
// Cf. the AuxiliarySwitches; establishes whether main or auxiliary RAM
@ -594,7 +562,7 @@ class MemoryMap {
// Contains a flag for every page in the final 128kb of memory, indicating whether it is
// currently subject to shadowing.
std::bitset<128> is_shadowed;
bool enable_all_pages_shadowing = true;
bool enable_all_pages_shadowing = false;
};
// TODO: branching below on region.read/write is predicated on the idea that extra scratch space