Updated interpreter

2014-07-25 02:55:30 +02:00
parent 8d8a171892
commit 1dc6358e4b
6 changed files with 40 additions and 52 deletions
--- a/nbfi/src/nbfi.c
+++ b/nbfi/src/nbfi.c
@@ -0,0 +1,107 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define OP_END 0
+#define OP_INC_DP 1
+#define OP_DEC_DP 2
+#define OP_INC_VAL 3
+#define OP_DEC_VAL 4
+#define OP_OUT 5
+#define OP_IN 6
+#define OP_JMP_FWD 7
+#define OP_JMP_BCK 8
+
+#define PROGRAM_SIZE 1048576
+#define MAX_SIZE 5024291
+#define DATA_SIZE 1638375
+
+#define STACK_PUSH(A) (stack[sp++] = A)
+#define STACK_POP() (stack[--sp])
+#define STACK_EMPTY() (sp == 0)
+#define STACK_FULL() (sp == MAX_SIZE)
+
+static inline void die(int code, const char* message){
+    fprintf(stderr, "%s", message);
+    exit(code);
+}
+
+struct instruction_t{
+    unsigned short operator;
+    unsigned short operand;
+};
+
+static struct instruction_t program[PROGRAM_SIZE];
+static unsigned short stack[MAX_SIZE];
+static unsigned int sp = 0;
+
+void compile(FILE* fp){
+    unsigned short pc = 0, jmp_pc;
+    int ip;
+    while ((ip = getc(fp)) != EOF && pc < MAX_SIZE){
+        switch (ip) {
+            case '>': program[pc].operator = OP_INC_DP; break;
+            case '<': program[pc].operator = OP_DEC_DP; break;
+            case '+': program[pc].operator = OP_INC_VAL; break;
+            case '-': program[pc].operator = OP_DEC_VAL; break;
+            case '.': program[pc].operator = OP_OUT; break;
+            case ',': program[pc].operator = OP_IN; break;
+            case '[':
+                program[pc].operator = OP_JMP_FWD;
+                if (STACK_FULL())
+                    die(1, "Cannot jump forwards: Stack is full.\n");
+                STACK_PUSH(pc);
+                break;
+            case ']':
+                if (STACK_EMPTY())
+                    die(1, "Cannot jump backwards: Stack is full.\n");
+                jmp_pc = STACK_POP();
+                program[pc].operator = OP_JMP_BCK;
+                program[pc].operand = jmp_pc;
+                program[jmp_pc].operand = pc;
+                break;
+            default:  
+                pc--;
+                break;
+        }
+        pc++;
+    }
+    if(!STACK_EMPTY())
+        die(1, "Program ends with non-empty stack.");
+    if(pc == MAX_SIZE)
+        die(1, "Program exceeds maximum program size.");
+    program[pc].operator = OP_END;
+}
+
+void execute(){
+    unsigned short data[DATA_SIZE], pc = 0;
+    unsigned int ptr = DATA_SIZE;
+    while (--ptr) data[ptr] = 0;
+    while (program[pc].operator != OP_END && ptr < DATA_SIZE){
+        switch (program[pc].operator){
+            case OP_INC_DP: ptr++; break;
+            case OP_DEC_DP: ptr--; break;
+            case OP_INC_VAL: data[ptr]++; break;
+            case OP_DEC_VAL: data[ptr]--; break;
+            case OP_OUT: putchar(data[ptr]); break;
+            case OP_IN: data[ptr] = (short unsigned int)getchar(); break;
+            case OP_JMP_FWD: if(!data[ptr]) { pc = program[pc].operand; } break;
+            case OP_JMP_BCK: if(data[ptr]) { pc = program[pc].operand; } break;
+            default: die(2, "Unknown instruction.");
+        }
+        pc++;
+    }
+    if(ptr == DATA_SIZE)
+        die(1, "Program used up too much memory.");
+}
+
+int main(int argc, const char * argv[]){
+    FILE *fp;
+    if(argc != 2)
+        die(1, "Wrong number of arguments supplied.\n");
+    if(!(fp = fopen(argv[1], "r")))
+        die(1, "File could not be opened.\n");
+    compile(fp);
+    fclose(fp);
+    execute();
+    return 0;
+}