99 lines
3.7 KiB
C++
99 lines
3.7 KiB
C++
#include "vm.h"
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#define MAX_EXTERNAL_CALLS 256
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#define MAX_DATA_STACK 256
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#define MAX_CALL_STACK 256
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enum OPS {
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OP_NOP = 0,
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OP_PUSH,
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OP_POP,
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OP_DUP,
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OP_LOAD,
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OP_LOADI,
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OP_STORE,
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OP_STOREI,
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OP_JMP,
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OP_JNT,
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OP_JTR,
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OP_JSR,
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OP_RET,
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OP_CALL,
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OP_ADD,
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OP_SUB,
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OP_MUL,
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OP_DIV,
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OP_MOD,
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OP_AND,
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OP_OR,
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OP_NOT,
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OP_NEG,
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OP_INC,
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OP_EQ,
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OP_NEQ,
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OP_LT,
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OP_GT
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};
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typedef void(*t_extcall)(t_stack&);
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t_extcall external_calls[MAX_EXTERNAL_CALLS];
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int numcallbacks = 0;
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const unsigned char* vm_program = nullptr;
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int vm_pc = 0;
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int vm_cycles = 0;
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t_stack vm_datastack;
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t_stack vm_callstack;
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unsigned char mem[65536];
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void vm_init(const unsigned char* program) {
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vm_program = program;
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vm_pc = 0;
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stack_init(vm_datastack, MAX_DATA_STACK);
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stack_init(vm_callstack, MAX_CALL_STACK);
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}
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inline unsigned short WORD() { vm_pc += 2; return vm_program[vm_pc - 2] + (vm_program[vm_pc - 1] << 8); }
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void vm_step() {
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char val;
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switch (vm_program[vm_pc++]) {
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case OP_NOP: vm_cycles++; break;
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case OP_PUSH: stack_push(vm_datastack, vm_program[vm_pc++]); vm_cycles++; break;
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case OP_POP: stack_pop(vm_datastack); vm_cycles++; break;
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case OP_DUP: stack_push(vm_datastack, stack_peek(vm_datastack)); vm_cycles++; break;
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case OP_LOAD: stack_push(vm_datastack, mem[WORD()]); vm_cycles++; break;
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case OP_LOADI: stack_push(vm_datastack, mem[WORD() + stack_pop(vm_datastack)]); vm_cycles++; break;
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case OP_STORE: mem[WORD()] = stack_pop(vm_datastack); vm_cycles++; break;
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case OP_STOREI: val = stack_pop(vm_datastack); mem[WORD() + stack_pop(vm_datastack)] = val; vm_cycles++; break;
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case OP_JMP: vm_pc = WORD(); vm_cycles++; break;
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case OP_JNT: if (stack_pop(vm_datastack) == 0) { vm_pc = WORD(); } vm_cycles++; break;
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case OP_JTR: if (stack_pop(vm_datastack) != 0) { vm_pc = WORD(); } vm_cycles++; break;
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case OP_JSR: stack_push(vm_callstack, vm_pc+2); vm_pc = WORD(); vm_cycles++; break;
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case OP_RET: vm_pc = stack_pop(vm_callstack); vm_cycles++; break;
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case OP_CALL: external_calls[vm_program[vm_pc++]](vm_datastack); vm_cycles++; break;
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case OP_ADD: stack_push(vm_datastack, stack_pop(vm_datastack) + stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_SUB: stack_push(vm_datastack, stack_pop(vm_datastack) - stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_MUL: stack_push(vm_datastack, stack_pop(vm_datastack) * stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_DIV: stack_push(vm_datastack, stack_pop(vm_datastack) / stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_MOD: stack_push(vm_datastack, stack_pop(vm_datastack) % stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_AND: stack_push(vm_datastack, stack_pop(vm_datastack) & stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_OR: stack_push(vm_datastack, stack_pop(vm_datastack) | stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_NOT: stack_push(vm_datastack, !stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_NEG: stack_push(vm_datastack, -stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_INC: stack_push(vm_datastack, stack_pop(vm_datastack)+1); vm_cycles++; break;
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case OP_EQ: stack_push(vm_datastack, stack_pop(vm_datastack) == stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_NEQ: stack_push(vm_datastack, stack_pop(vm_datastack) != stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_LT: stack_push(vm_datastack, stack_pop(vm_datastack) < stack_pop(vm_datastack)); vm_cycles++; break;
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case OP_GT: stack_push(vm_datastack, stack_pop(vm_datastack) > stack_pop(vm_datastack)); vm_cycles++; break;
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}
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}
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void vm_register_call(void(*callback)(t_stack&)) {
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external_calls[numcallbacks++] = callback;
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}
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