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/* Copyright (C) 2023 Aryadev Chavali
* You may distribute and modify this code under the terms of the
* GPLv2 license. You should have received a copy of the GPLv2
* license with this file. If not, please write to:
* aryadev@aryadevchavali.com.
* Created: 2023-10-23
* Author: Aryadev Chavali
* Description: An example virtual machine program which computes and
* prints fibonacci numbers. Note that by default the virtual machine
* just rolls overflows over, so this program will never terminate.
*/
#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <vm/inst.h>
#include <vm/runtime.h>
int main(void)
{
inst_t instructions[] = {
// MOV the values 1 and 1 to REG[0] and REG[1] respectively
INST_PUSH(WORD, 1),
INST_MOV(WORD, 0),
INST_PUSH(WORD, 1),
INST_MOV(WORD, 1),
// Print value at register 0 with newline.
INST_PUSH_REG(WORD, 0), // <-- #
INST_PRINT(WORD),
INST_PUSH(BYTE, '\n'),
INST_PRINT(CHAR),
// Print value at register 1 with newline
INST_PUSH_REG(WORD, 1),
INST_PRINT(WORD),
INST_PUSH(BYTE, '\n'),
INST_PRINT(CHAR),
/* Compute the next pair of fibonacci numbers */
// REG[0] + REG[1]
INST_PUSH_REG(WORD, 0),
INST_PUSH_REG(WORD, 1),
INST_PLUS(WORD),
// Mov REG[0] + REG[1] to REG[0]
INST_MOV(WORD, 0),
// REG[0] + REG[1]
INST_PUSH_REG(WORD, 0),
INST_PUSH_REG(WORD, 1),
INST_PLUS(WORD),
// Mov REG[0] + REG[1] to REG[1]
INST_MOV(WORD, 1),
// Jump to the point #
INST_JUMP_ABS(4),
INST_HALT,
};
byte stack[256];
vm_t vm = {0};
vm_load_stack(&vm, stack, ARR_SIZE(stack));
vm_load_program(&vm, instructions, ARR_SIZE(instructions));
err_t err = vm_execute_all(&vm);
if (err)
{
const char *error_str = err_as_cstr(err);
fprintf(stderr, "[ERROR]: %s\n", error_str);
fprintf(stderr, "[ERROR]: VM Trace:\n");
vm_print_all(&vm, stderr);
return 255 - err;
}
return 0;
}
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