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Introduces a further 128 bits of storage to eliminate the conditional in IsShadowed.

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This commit is contained in:
Thomas Harte 2021-02-28 15:14:32 -05:00
parent 8604b1786e
commit 496b6b5cfc
1 changed files with 22 additions and 16 deletions
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38
Machines/Apple/AppleIIgs/MemoryMap.hpp
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@ -187,6 +187,9 @@ class MemoryMap {
set_storage((first_rom_bank + c) << 16, &rom[c << 16], nullptr);
}
// Set shadowing as working from banks 0 and 1 (forever).
shadow_banks[0] = true;
// TODO: set 1Mhz flags.
// Apply initial language/auxiliary state.
@ -215,7 +218,11 @@ class MemoryMap {
void set_speed_register(uint8_t value) {
speed_register_ = value;
enable_all_pages_shadowing = speed_register_ & 0x10;
// Enable or disable shadowing from banks 0x02–0x80.
for(size_t c = 0x01; c < 0x40; c++) {
shadow_banks[c] = speed_register_ & 0x10;
}
}
void set_state_register(uint8_t value) {
@ -426,13 +433,13 @@ class MemoryMap {
// Text Page 1, main and auxiliary — $0400–$0800.
for(size_t c = 0x0400 >> shadow_shift; c < 0x0800 >> shadow_shift; c++) {
is_shadowed[c] = is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x01);
shadow_pages[c] = shadow_pages[c+auxiliary_offset] = !(shadow_register_ & 0x01);
}
// Text Page 2, main and auxiliary — 0x0800–0x0c00.
// TODO: on a ROM03 machine only.
for(size_t c = 0x0800 >> shadow_shift; c < 0x0c00 >> shadow_shift; c++) {
is_shadowed[c] = is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x20);
shadow_pages[c] = shadow_pages[c+auxiliary_offset] = !(shadow_register_ & 0x20);
}
// Hi-res graphics Page 1, main and auxiliary — $2000–$4000;
@ -445,8 +452,8 @@ class MemoryMap {
// (high-res graphics inhibit or auxiliary high res graphics inhibit) _and_ (super high-res inhibit).
//
for(size_t c = 0x2000 >> shadow_shift; c < 0x4000 >> shadow_shift; c++) {
is_shadowed[c] = !(shadow_register_ & 0x02);
is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x12);
shadow_pages[c] = !(shadow_register_ & 0x02);
shadow_pages[c+auxiliary_offset] = !(shadow_register_ & 0x12);
}
// Hi-res graphics Page 2, main and auxiliary — $4000–$6000;
@ -454,13 +461,13 @@ class MemoryMap {
//
// Test applied: much like that for page 1.
for(size_t c = 0x4000 >> shadow_shift; c < 0x6000 >> shadow_shift; c++) {
is_shadowed[c] = !(shadow_register_ & 0x04);
is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x14);
shadow_pages[c] = !(shadow_register_ & 0x04);
shadow_pages[c+auxiliary_offset] = !(shadow_register_ & 0x14);
}
// Residue of Super Hi-Res — $6000–$a000 (odd pages only).
for(size_t c = 0x6000 >> shadow_shift; c < 0xa000 >> shadow_shift; c++) {
is_shadowed[c+auxiliary_offset] = !(shadow_register_ & 0x08);
shadow_pages[c+auxiliary_offset] = !(shadow_register_ & 0x08);
}
}
@ -559,10 +566,12 @@ class MemoryMap {
// doctrinal reason for it to be whatever size it is now, just
// adjust as required.
// 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 = false;
// Shadow_pages: divides the final 128kb of memory into 1kb chunks and includes a flag to indicate whether
// each is a potential destination for shadowing.
//
// Shadow_banks: divides the whole 16mb of memory into 128kb chunks and includes a flag to indicate whether
// each is a potential source of shadowing.
std::bitset<128> shadow_pages, shadow_banks;
};
// TODO: branching below on region.read/write is predicated on the idea that extra scratch space
@ -571,7 +580,7 @@ class MemoryMap {
// TODO: somehow eliminate bank 0/1 conditional in IsShadowed.
#define MemoryMapRegion(map, address) map.regions[map.region_map[address >> 8]]
#define IsShadowed(map, region, address) map.is_shadowed[((&region.write[address] - map.ram_base) >> 10) & 127] && (map.enable_all_pages_shadowing || (address < 0x2'0000))
#define IsShadowed(map, region, address) (map.shadow_pages[((&region.write[address] - map.ram_base) >> 10) & 127] & map.shadow_banks[address >> 17])
#define MemoryMapRead(region, address, value) *value = region.read ? region.read[address] : 0xff
#define MemoryMapWrite(map, region, address, value) \
if(region.write) { \
@ -580,9 +589,6 @@ class MemoryMap {
map.shadow_base[is_shadowed][(&region.write[address] - map.ram_base) & map.shadow_mask[_mm_is_shadowed]] = *value; \
}
// const auto is_shadowed = region.flags & MemoryMap::Region::IsShadowed; \
// map.shadow_base[is_shadowed][(&region.write[address] - map.ram_base) & map.shadow_mask[is_shadowed]] = *value; \
// Quick notes on ::IsShadowed contortions:
//
// The objective is to support shadowing: