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Change tagging to assume sign extension.

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ARM and x86_64 require "real" pointers to be
sign-extended in their top bits. This means
a working pointer is guaranteed to have either "11"
as leading bits, or "00". So, to tag a "fake" pointer
which is an unboxed 32-bit integer, we simply toggle
the leading bit.
This commit is contained in:
Danila Fedorin 2020-09-17 18:30:55 -07:00
parent dfe47548cf
commit fb5a8a5a73
1 changed files with 7 additions and 7 deletions
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14
13/runtime.c
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@ -5,8 +5,8 @@
#include <stdio.h>
#include "runtime.h"
#define INT_MARKER (1l << 63)
#define IS_INT(n) ((uint64_t) n & INT_MARKER)
#define TOGGLE_MARK(n) ((uint64_t) n ^ ((uint64_t) 1 << 63))
#define IS_MARKED(n) ((((uint64_t) n) ^ ((uint64_t) n << 1)) & ((uint64_t) 1 << 63))
struct node_base* alloc_node() {
struct node_base* new_node = malloc(sizeof(struct node_app));
@ -25,7 +25,7 @@ struct node_app* alloc_app(struct node_base* l, struct node_base* r) {
}
struct node_num* alloc_num(int32_t n) {
return (struct node_num*) (INT_MARKER | n);
return (struct node_num*) TOGGLE_MARK(n);
}
struct node_global* alloc_global(void (*f)(struct gmachine*), int32_t a) {
@ -50,7 +50,7 @@ void free_node_direct(struct node_base* n) {
}
void gc_visit_node(struct node_base* n) {
if(IS_INT(n) || n->gc_reachable) return;
if(IS_MARKED(n) || n->gc_reachable) return;
n->gc_reachable = 1;
if(n->tag == NODE_APP) {
@ -170,7 +170,7 @@ void gmachine_split(struct gmachine* g, size_t n) {
}
struct node_base* gmachine_track(struct gmachine* g, struct node_base* b) {
if(IS_INT(b)) return b;
if(IS_MARKED(b)) return b;
g->gc_node_count++;
b->gc_next = g->gc_nodes;
g->gc_nodes = b;
@ -210,7 +210,7 @@ void unwind(struct gmachine* g) {
while(1) {
struct node_base* peek = stack_peek(s, 0);
if(IS_INT(peek)) {
if(IS_MARKED(peek)) {
break;
} else if(peek->tag == NODE_APP) {
struct node_app* n = (struct node_app*) peek;
@ -238,7 +238,7 @@ void unwind(struct gmachine* g) {
extern void f_main(struct gmachine* s);
void print_node(struct node_base* n) {
if(IS_INT(n)) {
if(IS_MARKED(n)) {
printf("%d", (int32_t) n);
} else if(n->tag == NODE_APP) {
struct node_app* app = (struct node_app*) n;