124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
#include "arm.h"
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#include "isa-arm.h"
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#include "isa-inlines.h"
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#include "isa-thumb.h"
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#include <limits.h>
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static inline enum RegisterBank _ARMSelectBank(enum PrivilegeMode);
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void ARMSetPrivilegeMode(struct ARMCore* cpu, enum PrivilegeMode mode) {
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if (mode == cpu->privilegeMode) {
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// Not switching modes after all
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return;
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}
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enum RegisterBank newBank = _ARMSelectBank(mode);
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enum RegisterBank oldBank = _ARMSelectBank(cpu->privilegeMode);
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if (newBank != oldBank) {
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// Switch banked registers
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if (mode == MODE_FIQ || cpu->privilegeMode == MODE_FIQ) {
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int oldFIQBank = oldBank == BANK_FIQ;
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int newFIQBank = newBank == BANK_FIQ;
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cpu->bankedRegisters[oldFIQBank][2] = cpu->gprs[8];
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cpu->bankedRegisters[oldFIQBank][3] = cpu->gprs[9];
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cpu->bankedRegisters[oldFIQBank][4] = cpu->gprs[10];
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cpu->bankedRegisters[oldFIQBank][5] = cpu->gprs[11];
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cpu->bankedRegisters[oldFIQBank][6] = cpu->gprs[12];
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cpu->gprs[8] = cpu->bankedRegisters[newFIQBank][2];
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cpu->gprs[9] = cpu->bankedRegisters[newFIQBank][3];
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cpu->gprs[10] = cpu->bankedRegisters[newFIQBank][4];
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cpu->gprs[11] = cpu->bankedRegisters[newFIQBank][5];
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cpu->gprs[12] = cpu->bankedRegisters[newFIQBank][6];
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}
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cpu->bankedRegisters[oldBank][0] = cpu->gprs[ARM_SP];
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cpu->bankedRegisters[oldBank][1] = cpu->gprs[ARM_LR];
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cpu->gprs[ARM_SP] = cpu->bankedRegisters[newBank][0];
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cpu->gprs[ARM_LR] = cpu->bankedRegisters[newBank][1];
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cpu->bankedSPSRs[oldBank] = cpu->spsr.packed;
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cpu->spsr.packed = cpu->bankedSPSRs[newBank];
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}
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cpu->privilegeMode = mode;
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}
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static inline enum RegisterBank _ARMSelectBank(enum PrivilegeMode mode) {
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switch (mode) {
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case MODE_USER:
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case MODE_SYSTEM:
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// No banked registers
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return BANK_NONE;
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case MODE_FIQ:
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return BANK_FIQ;
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case MODE_IRQ:
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return BANK_IRQ;
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case MODE_SUPERVISOR:
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return BANK_SUPERVISOR;
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case MODE_ABORT:
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return BANK_ABORT;
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case MODE_UNDEFINED:
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return BANK_UNDEFINED;
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default:
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// This should be unreached
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return BANK_NONE;
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}
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}
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void ARMInit(struct ARMCore* cpu) {
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cpu->memory = 0;
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cpu->board = 0;
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}
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void ARMAssociateMemory(struct ARMCore* cpu, struct ARMMemory* memory) {
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cpu->memory = memory;
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}
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void ARMAssociateBoard(struct ARMCore* cpu, struct ARMBoard* board) {
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cpu->board = board;
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board->cpu = cpu;
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}
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void ARMReset(struct ARMCore* cpu) {
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int i;
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for (i = 0; i < 16; ++i) {
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cpu->gprs[i] = 0;
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}
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for (i = 0; i < 6; ++i) {
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cpu->bankedRegisters[i][0] = 0;
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cpu->bankedRegisters[i][1] = 0;
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cpu->bankedRegisters[i][2] = 0;
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cpu->bankedRegisters[i][3] = 0;
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cpu->bankedRegisters[i][4] = 0;
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cpu->bankedRegisters[i][5] = 0;
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cpu->bankedRegisters[i][6] = 0;
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cpu->bankedSPSRs[i] = 0;
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}
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cpu->cpsr.packed = MODE_SYSTEM;
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cpu->spsr.packed = 0;
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cpu->cycles = 0;
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cpu->nextEvent = 0;
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cpu->shifterOperand = 0;
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cpu->shifterCarryOut = 0;
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cpu->executionMode = MODE_THUMB;
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_ARMSetMode(cpu, MODE_ARM);
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cpu->board->reset(cpu->board);
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}
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void ARMRun(struct ARMCore* cpu) {
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if (cpu->executionMode == MODE_THUMB) {
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ThumbStep(cpu);
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} else {
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ARMStep(cpu);
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}
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if (cpu->cycles >= cpu->nextEvent) {
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cpu->board->processEvents(cpu->board);
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}
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}
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