yaps/samples/manual_vm/vm_run_sample.c at main · NoAddr/yaps · GitHub

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#include <stdio.h>
#include <stdint.h>

__declspec(dllexport) const uint8_t* vpc = NULL;

typedef enum {
    VM_HALT = 0,
    VM_MOV_IMM,
    VM_MOV,
    VM_ADD,
    VM_SUB,
    VM_MUL,
    VM_DIV,
    VM_TEST,
    VM_JG,
    VM_JL,
    VM_JGE,
    VM_JLE,
    VM_EQ
} VmOpcode;

int32_t R[4] = {0};
int32_t cmp_flag = 0;

void vm_run(const uint8_t* code) {
    vpc = code;

    while (1) {
        uint8_t opcode = *vpc++;

        switch (opcode) {
            case VM_HALT:
                return;
            case VM_MOV_IMM:
                R[*vpc] = *(const int32_t*)(vpc + 1);
                vpc += 5;
                break;
            case VM_MOV:
                R[*vpc] = R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_ADD:
                R[*vpc] += R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_SUB:
                R[*vpc] -= R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_MUL:
                R[*vpc] *= R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_DIV:
                R[*vpc] /= R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_TEST:
                cmp_flag = R[*vpc] - R[*(vpc + 1)];
                vpc += 2;
                break;
            case VM_JG:
                if (cmp_flag > 0) {
                    vpc += *(const int32_t*)vpc;
                } else {
                    vpc += 4;
                }
                break;
            case VM_JL:
                if (cmp_flag < 0) {
                    vpc += *(const int32_t*)vpc;
                } else {
                    vpc += 4;
                }
                break;
            case VM_JGE:
                if (cmp_flag >= 0) {
                    vpc += *(const int32_t*)vpc;
                } else {
                    vpc += 4;
                }
                break;
            case VM_JLE:
                if (cmp_flag <= 0) {
                    vpc += *(const int32_t*)vpc;
                } else {
                    vpc += 4;
                }
                break;
            case VM_EQ:
                if (cmp_flag == 0) {
                    vpc += *(const int32_t*)vpc;
                } else {
                    vpc += 4;
                }
                break;
            default:
                printf("Error: Unknown Opcode 0x%02X\n", opcode);
                return;
        }
    }
}

uint8_t program[] = {
    VM_MOV_IMM, 0, 0x00, 0x00, 0x00, 0x00,
    VM_MOV_IMM, 1, 0x01, 0x00, 0x00, 0x00,
    VM_MOV_IMM, 2, 0x0A, 0x00, 0x00, 0x00,
    VM_MOV_IMM, 3, 0x01, 0x00, 0x00, 0x00,

    VM_TEST, 1, 2,
    VM_JG, 0x12, 0x00, 0x00, 0x00,

    VM_ADD, 0, 1,
    VM_ADD, 1, 3,

    VM_TEST, 3, 3,
    VM_EQ, 0xEE, 0xFF, 0xFF, 0xFF,

    VM_HALT
};

int main(void) {
    printf("Starting VM Execution...\n");

    vm_run(program);

    printf("VM execution finished.\n");
    printf("Result in R0 (Sum 1 to 10): %d\n", R[0]);
    printf("Final vpc pointer address: %p\n", (void*)vpc);

    return 0;
}