From 700c3b1d1b3ed835ffab3fd502ab91baba8e2d1f Mon Sep 17 00:00:00 2001 From: Aryadev Chavali Date: Mon, 1 Sep 2025 21:26:01 +0100 Subject: Move implementation files into their own folder main.c and test.c generate binary executables so they can stay in the main folder, but the rest can go into their own dedicated folder to make it look nicer --- impl/tag.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 impl/tag.c (limited to 'impl/tag.c') diff --git a/impl/tag.c b/impl/tag.c new file mode 100644 index 0000000..e6396cc --- /dev/null +++ b/impl/tag.c @@ -0,0 +1,76 @@ +/* Copyright (C) 2025 Aryadev Chavali + + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + * FOR A PARTICULAR PURPOSE. See the Unlicense for details. + + * You may distribute and modify this code under the terms of the Unlicense, + * which you should have received a copy of along with this program. If not, + * please go to . + + * Created: 2025-08-19 + * Description: Pointer tagging + */ + +#include +#include + +#include + +lisp_t *tag_int(i64 i) +{ + return TAG((u64)i, INT); +} + +lisp_t *tag_sym(char *str) +{ + return TAG((u64)str, SYM); +} + +lisp_t *tag_vec(vec_t *vec) +{ + return TAG((u64)vec, VEC); +} + +lisp_t *tag_cons(cons_t *cons) +{ + return TAG((u64)cons, CONS); +} + +tag_t get_tag(lisp_t *lisp) +{ + static_assert(NUM_TAGS == 5); + if (!lisp) + return TAG_NIL; + else if (IS_TAG(lisp, INT)) + return TAG_INT; + + return (u64)lisp & 0xFF; +} + +i64 as_int(lisp_t *obj) +{ + assert(IS_TAG(obj, INT)); + u64 p_obj = (u64)obj; + return UNTAG(p_obj, INT) | // Delete the tag + (NTH_BYTE(p_obj, 7) & 0x80) << 56 // duplicate the MSB (preserve sign) + ; +} + +char *as_sym(lisp_t *obj) +{ + assert(IS_TAG(obj, SYM)); + return (char *)UNTAG(obj, SYM); +} + +cons_t *as_cons(lisp_t *obj) +{ + assert(IS_TAG(obj, CONS)); + return (cons_t *)UNTAG(obj, CONS); +} + +vec_t *as_vec(lisp_t *obj) +{ + assert(IS_TAG(obj, VEC)); + return (vec_t *)UNTAG(obj, VEC); +} -- cgit v1.2.3-13-gbd6f