Simple_Language/SM.h at master · hotTeaFun/Simple_Language · GitHub

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/***************************************************************************
Stack Machine
***************************************************************************/
/*=========================================================================
DECLARATIONS
=========================================================================*/
/* OPERATIONS: Internal Representation */
enum code_ops { HALT, STORE, JMP_FALSE, GOTO,
                DATA, LD_INT, LD_VAR,
                READ_INT, WRITE_INT,
                LT, EQ, GT, ADD, SUB, MULT, DIV, PWR };
/* OPERATIONS: External Representation */
char *op_name[] = {"halt", "store", "jmp_false", "goto",
                   "data", "ld_int", "ld_var",
                   "in_int", "out_int",
                   "lt", "eq", "gt", "add", "sub", "mult", "div", "pwr" };
struct instruction
{
enum code_ops op;
int arg;
};
/* CODE Array */
struct instruction code[999];
/* RUN-TIME Stack */
int stack[999];
/*-------------------------------------------------------------------------
Registers
-------------------------------------------------------------------------*/
int  pc  = 0;
struct instruction ir;
int  ar   = 0;
int  top = 0;
char ch;
/*=========================================================================
Fetch Execute Cycle
=========================================================================*/
void fetch_execute_cycle()
{
do { /*printf( "PC = %3d IR.arg = %8d AR = %3d Top = %3d,%8d\n",
pc, ir.arg, ar, top, stack[top]); */
/* Fetch
*/
ir = code[pc++];
/* Execute
*/
switch (ir.op) {
case HALT      : printf( "halt\n" );                             break;
case READ_INT  : printf( "Input: " );
                 scanf( "%ld", &stack[ar+ir.arg] );              break;
case WRITE_INT : printf( "Output: %d\n", stack[top--] );         break;
case STORE     : stack[ir.arg] = stack[top--];                   break;
case JMP_FALSE : if ( stack[top--] == 0 )
                   pc = ir.arg;                                  break;
case GOTO      : pc = ir.arg;                                    break;
case DATA      : top = top + ir.arg;                             break;
case LD_INT    : stack[++top] = ir.arg;                          break;
case LD_VAR    : stack[++top] = stack[ar+ir.arg];                break;
case LT        : if ( stack[top-1] < stack[top] )
                   stack[--top] = 1;
                 else stack[--top] = 0;                          break;
case EQ : if ( stack[top-1] == stack[top] )
                   stack[--top] = 1;
                 else stack[--top] = 0;                          break;
case GT : if ( stack[top-1] > stack[top] )
                   stack[--top] = 1;
                 else stack[--top] = 0;                          break;
case ADD : stack[top-1] = stack[top-1] + stack[top];
                    top--;                                       break;
case SUB : stack[top-1] = stack[top-1] - stack[top];
                    top--;                                       break;
case MULT: stack[top-1] = stack[top-1] * stack[top];
                    top--;                                       break;
case DIV : stack[top-1] = stack[top-1] / stack[top];
                    top--;                                       break;
case PWR : stack[top-1] = stack[top-1] * stack[top];
                    top--;                                       break;
default  : printf( "%sInternal Error: Memory Dump\n" );          break;
    }
}
while (ir.op != HALT);
}
/*************************** End Stack Machine **************************/