d08c2860da
ysyx_22040000 李心杨 Linux calcite 6.6.19 #1-NixOS SMP PREEMPT_DYNAMIC Fri Mar 1 12:35:11 UTC 2024 x86_64 GNU/Linux 16:26:21 up 4 days 3:32, 2 users, load average: 0.85, 0.91, 0.95
98 lines
2.7 KiB
C
98 lines
2.7 KiB
C
/* from http://rosettacode.org/wiki/Execute_Brain****#C */
|
|
/* This is the Neutron brainfuck interpreter.
|
|
* It's rather small and dense, but still readable, more or less.
|
|
*
|
|
* Robert de Bath -- 2013.
|
|
*/
|
|
#include <am.h>
|
|
#include <klib.h>
|
|
#include <io.h>
|
|
|
|
static const char *prog =
|
|
#include "mandelbrot.h"
|
|
;
|
|
|
|
struct bfi { char cmd; struct bfi *next, *jmp; };
|
|
struct mem { char val; struct mem *next, *prev; };
|
|
|
|
static inline void putch2(char c) {
|
|
static int x = 0, y = 0;
|
|
if (c == '\n') {
|
|
y ++;
|
|
x = 0;
|
|
} else {
|
|
if (x % 2 == 0) {
|
|
print_char(c, y, x / 2);
|
|
screen_refresh();
|
|
}
|
|
x ++;
|
|
}
|
|
}
|
|
|
|
void bf() {
|
|
int ch;
|
|
struct bfi *p=0, *n=0, *j=0, *pgm = 0;
|
|
struct mem *m = malloc(sizeof(*m));
|
|
memset(m, 0, sizeof(*m));
|
|
screen_clear();
|
|
|
|
/*
|
|
* For each character, if it's a valid BF command add it onto the
|
|
* end of the program. If the input is stdin use the '!' character
|
|
* to mark the end of the program and the start of the data, but
|
|
* only if we have a complete program. The 'j' variable points
|
|
* at the list of currently open '[' commands, one is matched off
|
|
* by each ']'. A ']' without a matching '[' is not a legal BF
|
|
* command and so is ignored. If there are any '[' commands left
|
|
* over at the end they are not valid BF commands and so are ignored.
|
|
*/
|
|
const char *s = prog;
|
|
while((ch = *(s ++)) != '\0') {
|
|
if (ch == '<' || ch == '>' || ch == '+' || ch == '-' ||
|
|
ch == ',' || ch == '.' || ch == '[' || (ch == ']' && j)) {
|
|
if ((n = malloc(sizeof(*n))) == NULL) {
|
|
printf("malloc failed! exiting...\n");
|
|
halt(1);
|
|
}
|
|
memset(n, 0, sizeof(*n));
|
|
if (p) p->next = n; else pgm = n;
|
|
n->cmd = ch; p = n;
|
|
if (n->cmd == '[') { n->jmp=j; j = n; }
|
|
else if (n->cmd == ']') {
|
|
n->jmp = j; j = j->jmp; n->jmp->jmp = n;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Ignore any left over '[' commands */
|
|
while(j) { p = j; j = j->jmp; p->jmp = 0; p->cmd = ' '; }
|
|
|
|
/* Execute the loaded BF program */
|
|
for(n=pgm; n; n=n->next) {
|
|
switch(n->cmd) {
|
|
case '+': m->val++; break;
|
|
case '-': m->val--; break;
|
|
case '.': putch2(m->val); break;
|
|
case ',': if((ch=*(s ++))!='\0') m->val=ch; break;
|
|
case '[': if (m->val == 0) n=n->jmp; break;
|
|
case ']': if (m->val != 0) n=n->jmp; break;
|
|
case '<':
|
|
if (!(m=m->prev)) {
|
|
printf("Hit start of tape\n");
|
|
halt(1);
|
|
}
|
|
break;
|
|
case '>':
|
|
if (m->next == 0) {
|
|
if ((m->next = malloc(sizeof(*m))) == NULL) {
|
|
printf("malloc failed! exiting...\n");
|
|
halt(1);
|
|
}
|
|
memset(m->next, 0, sizeof(*m));
|
|
m->next->prev = m;
|
|
}
|
|
m=m->next;
|
|
break;
|
|
}
|
|
}
|
|
}
|