frame layout refactor

c/frame_layout.h

@@ -0,0 +1,81 @@
+#ifndef FRAME_LAYOUT_H
+#include "forkable_stack.h"
+#include "bytecode.h"
+#include <jansson.h>
+
+struct closure {
+  struct bytecode* bc;
+  uint16_t* pc;
+};
+
+typedef union frame_elem {
+  FORKABLE_STACK_HEADER;
+  struct closure closure;
+  json_t* jsonval;
+} *frame_ptr;
+
+/*
+ * Frame layout
+ * fr[0] - FORKABLE_STACK_HEADER (next pointer)
+ * fr[1] - self (used to store return addresses, etc)
+ * fr[2...nclosures+2] - closure params
+ * fr[nclosures+2..nclosures+nlocals+2] - local variables
+ */
+
+static int frame_size(struct bytecode* bc) {
+  return sizeof(union frame_elem) * (bc->nclosures + bc->nlocals + 2);
+}
+
+static struct closure* frame_self(frame_ptr fr) {
+  return &fr[1].closure;
+}
+
+static struct closure* frame_closure_arg(frame_ptr fr, int closure) {
+  assert(closure >= 0);
+  assert(closure < frame_self(fr)->bc->nclosures);
+  return &fr[2+closure].closure;
+}
+
+static json_t** frame_local_var(frame_ptr fr, int var) {
+  assert(var >= 0);
+  assert(var < frame_self(fr)->bc->nlocals);
+  return &fr[2 + frame_self(fr)->bc->nclosures + var].jsonval;
+}
+
+
+static frame_ptr frame_current(struct forkable_stack* stk) {
+  frame_ptr fp = forkable_stack_peek(stk);
+  struct bytecode* bc = frame_self(fp)->bc;
+  assert(frame_self(fp)->pc >= bc->code && frame_self(fp)->pc < bc->code + bc->codelen);
+  return fp;
+}
+
+static struct bytecode* frame_current_bytecode(struct forkable_stack* stk) {
+  return frame_self(frame_current(stk))->bc;
+}
+static uint16_t** frame_current_pc(struct forkable_stack* stk) {
+  return &frame_self(frame_current(stk))->pc;
+}
+
+
+
+
+static void frame_push(struct forkable_stack* stk, struct bytecode* bc) {
+  frame_ptr fp = forkable_stack_push(stk, frame_size(bc));
+  frame_self(fp)->bc = bc;
+  frame_self(fp)->pc = bc->code;
+}
+
+static void frame_push_backtrack(struct forkable_stack* stk, 
+                                      struct bytecode* bc, uint16_t* pc) {
+  frame_ptr fp = forkable_stack_push(stk, sizeof(union frame_elem) * 2);
+  frame_self(fp)->bc = bc;
+  frame_self(fp)->pc = pc;
+}
+
+
+static void frame_pop(struct forkable_stack* stk) {
+  forkable_stack_pop(stk);
+}
+
+#endif