Added:
* calculate data/instruction physical addresses from a virtual address memory_addresses_t calculate_physical_address(const int run_mode, const uint16_t a); * check if a 'memory_address_t'-address would cause a fault void check_address(const bool trap_on_failure, const bool is_write, const memory_addresses_t & addr, const bool word_mode, const bool is_data, const int run_mode);
This commit is contained in:
folkert van heusden
parent
6f20ce864f
commit
3ef8bd930d
2 changed files with 151 additions and 2 deletions
140
bus.cpp
140
bus.cpp
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@ -324,6 +324,146 @@ void bus::setMMR2(const uint16_t value)
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MMR2 = value;
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}
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memory_addresses_t bus::calculate_physical_address(const int run_mode, const uint16_t a)
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{
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const uint8_t apf = a >> 13; // active page field
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uint32_t physical_instruction = pages[run_mode][0][apf].par * 64;
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uint32_t physical_data = pages[run_mode][1][apf].par * 64;
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uint16_t p_offset = a & 8191; // page offset
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physical_instruction += p_offset;
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physical_data += p_offset;
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if (MMR0 & 1) { // MMU enabled?
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if ((MMR3 & 16) == 0) { // offset is 18bit
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physical_instruction &= 0x3ffff;
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physical_data &= 0x3ffff;
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}
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}
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return { a, apf, physical_instruction, physical_data };
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}
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void bus::check_address(const bool trap_on_failure, const bool is_write, const memory_addresses_t & addr, const bool word_mode, const bool is_data, const int run_mode)
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{
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// check for odd address access
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if ((addr.virtual_address & 1) && word_mode == 0) {
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if (is_write)
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pages[run_mode][is_data][addr.apf].pdr |= 1 << 7;
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c->schedule_trap(004); // invalid access
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throw 5;
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}
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if (!trap_on_failure)
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return;
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// check access to page
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if ((MMR0 & (1 << 9)) || c->get_34()) {
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const int access_control = pages[run_mode][is_data][addr.apf].pdr & 7;
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// write
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if (is_write && access_control != 6) {
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c->schedule_trap(0250); // invalid address
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if (is_write)
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pages[run_mode][is_data][addr.apf].pdr |= 1 << 7;
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if ((MMR0 & 0160000) == 0) {
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MMR0 &= 017777;
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MMR0 |= 1 << 13; // read-only
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MMR0 &= ~(3 << 5);
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MMR0 |= run_mode << 5; // TODO: kernel-mode or user-mode when a trap occurs in user-mode?
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MMR0 &= ~14; // add current page
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MMR0 |= addr.apf << 1;
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}
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DOLOG(debug, true, "MMR0: %06o", MMR0);
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throw 1;
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}
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// read
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if (!is_write) {
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if (access_control == 0 || access_control == 1 || access_control == 3 || access_control == 4 || access_control == 7) {
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c->schedule_trap(0250); // invalid address
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if (is_write)
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pages[run_mode][is_data][addr.apf].pdr |= 1 << 7; // TODO: D/I
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if ((MMR0 & 0160000) == 0) {
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MMR0 &= 017777;
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if (access_control == 0 || access_control == 4)
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MMR0 |= 1 << 15; // not resident
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else
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MMR0 |= 1 << 13; // read-only
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MMR0 &= ~(3 << 5);
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MMR0 |= run_mode << 5;
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MMR0 &= ~14; // add current page
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MMR0 |= addr.apf << 1;
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}
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throw 2;
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}
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}
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}
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// beyond physical range?
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if ((is_data && addr.physical_data >= n_pages * 8192) || (!is_data && addr.physical_instruction >= n_pages * 8192)) {
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if ((MMR0 & 0160000) == 0) {
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MMR0 &= 017777;
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MMR0 |= 1 << 15; // non-resident
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MMR0 &= ~14; // add current page
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MMR0 |= addr.apf << 1;
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MMR0 &= ~(3 << 5);
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MMR0 |= run_mode << 5;
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}
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if (is_write)
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pages[run_mode][is_data][addr.apf].pdr |= 1 << 7; // TODO: D/I
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c->schedule_trap(04);
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throw 3;
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}
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// check if invalid access IN a page
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uint16_t pdr_len = (pages[run_mode][is_data][addr.apf].pdr >> 8) & 127;
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uint16_t pdr_cmp = (addr.virtual_address >> 6) & 127;
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bool direction = pages[run_mode][is_data][addr.apf].pdr & 8; // TODO: D/I
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if ((pdr_cmp > pdr_len && direction == false) || (pdr_cmp < pdr_len && direction == true)) {
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c->schedule_trap(0250); // invalid access
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if ((MMR0 & 0160000) == 0) {
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MMR0 &= 017777;
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MMR0 |= 1 << 14; // length
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MMR0 &= ~14; // add current page
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MMR0 |= addr.apf << 1;
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MMR0 &= ~(3 << 5);
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MMR0 |= run_mode << 5;
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}
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if (is_write)
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pages[run_mode][0][addr.apf].pdr |= 1 << 7; // TODO: D/I
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throw 4;
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}
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}
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uint32_t bus::calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only, const bool is_data)
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{
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uint32_t m_offset = a;
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13
bus.h
13
bus.h
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@ -57,8 +57,14 @@ class tty;
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typedef enum { d_space, i_space } d_i_space_t;
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typedef struct
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{
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typedef struct {
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uint16_t virtual_address;
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uint8_t apf; // active page field
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uint32_t physical_instruction;
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uint32_t physical_data;
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} memory_addresses_t;
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typedef struct {
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uint16_t par, pdr;
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} page_t;
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@ -140,4 +146,7 @@ public:
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uint16_t get_switch_register() const { return switch_register; }
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uint32_t calculate_physical_address(const int run_mode, const uint16_t a, const bool trap_on_failure, const bool is_write, const bool peek_only, const bool is_data);
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memory_addresses_t calculate_physical_address(const int run_mode, const uint16_t a);
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void check_address(const bool trap_on_failure, const bool is_write, const memory_addresses_t & addr, const bool word_mode, const bool is_data, const int run_mode);
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};
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