Add intrinsic for call/cc

* libguile/intrinsics.h: Add "capture-continuation" intrinsic.
* libguile/vm-engine.c (call/cc): Rework to use capture_continuation
  intrinsic.
* libguile/vm.c (capture_continuation): New intrinsic.

libguile/intrinsics.h

@@ -24,6 +24,8 @@
 #error intrinsics.h is private and uninstalled
 #endif
 
+#include <setjmp.h>
+
 #include <libguile/scm.h>
 
 
@@ -52,6 +54,7 @@ typedef void (*scm_t_thread_u32_u32_scm_u8_u8_intrinsic) (scm_thread*, uint32_t,
 typedef SCM (*scm_t_scm_from_scm_scm_scmp_sp_intrinsic) (SCM, SCM, SCM*,
                                                          const union scm_vm_stack_element*);
 typedef void (*scm_t_thread_scm_noreturn_intrinsic) (scm_thread*, SCM) SCM_NORETURN;
+typedef SCM (*scm_t_scm_from_thread_regs_intrinsic) (scm_thread*, jmp_buf*);
 
 #define SCM_FOR_ALL_VM_INTRINSICS(M) \
   M(scm_from_scm_scm, add, "add", ADD) \
@@ -103,6 +106,7 @@ typedef void (*scm_t_thread_scm_noreturn_intrinsic) (scm_thread*, SCM) SCM_NORET
   M(thread, push_interrupt_frame, "push-interrupt-frame", PUSH_INTERRUPT_FRAME) \
   M(scm_from_scm_scm_scmp_sp, foreign_call, "foreign-call", FOREIGN_CALL) \
   M(thread_scm_noreturn, reinstate_continuation_x, "reinstate-continuation!", REINSTATE_CONTINUATION_X) \
+  M(scm_from_thread_regs, capture_continuation, "capture-continuation", CAPTURE_CONTINUATION) \
   /* Add new intrinsics here; also update scm_bootstrap_intrinsics.  */
 
 enum scm_vm_intrinsic

libguile/vm-engine.c

@@ -756,18 +756,10 @@ VM_NAME (scm_thread *thread, jmp_buf *registers, int resume)
    */
   VM_DEFINE_OP (15, call_cc, "call/cc", OP1 (X32))
     {
-      SCM vm_cont, cont;
+      SCM cont;
-      scm_t_dynstack *dynstack;
 
       SYNC_IP ();
-      dynstack = scm_dynstack_capture_all (&thread->dynstack);
+      cont = scm_vm_intrinsics.capture_continuation (thread, registers);
-      vm_cont = scm_i_vm_capture_stack (VP->stack_top,
-                                        SCM_FRAME_DYNAMIC_LINK (VP->fp),
-                                        SCM_FRAME_PREVIOUS_SP (VP->fp),
-                                        SCM_FRAME_RETURN_ADDRESS (VP->fp),
-                                        dynstack,
-                                        0);
-      cont = scm_i_make_continuation (registers, thread, vm_cont);
 
       RESET_FRAME (2);
 

libguile/vm.c

@@ -1298,6 +1298,20 @@ reinstate_continuation_x (scm_thread *thread, SCM cont)
   scm_i_reinstate_continuation (cont);
 }
 
+static SCM
+capture_continuation (scm_thread *thread, jmp_buf *registers)
+{
+  struct scm_vm *vp = &thread->vm;
+  SCM vm_cont =
+    scm_i_vm_capture_stack (vp->stack_top,
+                            SCM_FRAME_DYNAMIC_LINK (vp->fp),
+                            SCM_FRAME_PREVIOUS_SP (vp->fp),
+                            SCM_FRAME_RETURN_ADDRESS (vp->fp),
+                            scm_dynstack_capture_all (&thread->dynstack),
+                            0);
+  return scm_i_make_continuation (registers, thread, vm_cont);
+}
+
 SCM
 scm_call_n (SCM proc, SCM *argv, size_t nargs)
 {
@@ -1642,6 +1656,7 @@ scm_bootstrap_vm (void)
   scm_vm_intrinsics.bind_kwargs = bind_kwargs;
   scm_vm_intrinsics.push_interrupt_frame = push_interrupt_frame;
   scm_vm_intrinsics.reinstate_continuation_x = reinstate_continuation_x;
+  scm_vm_intrinsics.capture_continuation = capture_continuation;
 
   sym_vm_run = scm_from_latin1_symbol ("vm-run");
   sym_vm_error = scm_from_latin1_symbol ("vm-error");