From e4b913cb1515b3131ca51fced5bd55ec31e8aa6f Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Wed, 30 Oct 2013 10:03:46 +0900
Subject: [PATCH] add OP_TAILCALL

---
 include/picrin/irep.h |  1 +
 src/codegen.c         |  3 +++
 src/vm.c              | 18 ++++++++++++++++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/picrin/irep.h b/include/picrin/irep.h
index 4f0ce8ba..efda468f 100644
--- a/include/picrin/irep.h
+++ b/include/picrin/irep.h
@@ -18,6 +18,7 @@ enum pic_opcode {
   OP_JMP,
   OP_JMPIF,
   OP_CALL,
+  OP_TAILCALL,
   OP_RET,
   OP_LAMBDA,
   OP_CONS,
diff --git a/src/codegen.c b/src/codegen.c
index 7e1eb742..02032d4b 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -744,6 +744,9 @@ print_irep(pic_state *pic, struct pic_irep *irep)
     case OP_CALL:
       printf("OP_CALL\t%d\n", irep->code[i].u.i);
       break;
+    case OP_TAILCALL:
+      printf("OP_TAILCALL\t%d\n", irep->code[i].u.i);
+      break;
     case OP_RET:
       puts("OP_RET");
       break;
diff --git a/src/vm.c b/src/vm.c
index d6685f41..1c10700e 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -192,8 +192,8 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
     &&L_OP_POP, &&L_OP_PUSHNIL, &&L_OP_PUSHTRUE, &&L_OP_PUSHFALSE, &&L_OP_PUSHFLOAT,
     &&L_OP_PUSHINT, &&L_OP_PUSHCONST, &&L_OP_GREF, &&L_OP_GSET, &&L_OP_LREF,
     &&L_OP_LSET, &&L_OP_CREF, &&L_OP_CSET, &&L_OP_JMP, &&L_OP_JMPIF, &&L_OP_CALL,
-    &&L_OP_RET, &&L_OP_LAMBDA, &&L_OP_CONS, &&L_OP_CAR, &&L_OP_CDR, &&L_OP_NILP,
-    &&L_OP_ADD, &&L_OP_SUB, &&L_OP_MUL, &&L_OP_DIV,
+    &&L_OP_TAILCALL, &&L_OP_RET, &&L_OP_LAMBDA, &&L_OP_CONS, &&L_OP_CAR, &&L_OP_CDR,
+    &&L_OP_NILP, &&L_OP_ADD, &&L_OP_SUB, &&L_OP_MUL, &&L_OP_DIV,
     &&L_OP_EQ, &&L_OP_LT, &&L_OP_LE, &&L_OP_STOP
   };
 #endif
@@ -358,6 +358,20 @@ pic_apply(pic_state *pic, struct pic_proc *proc, pic_value argv)
 	JUMP;
       }
     }
+    CASE(OP_TAILCALL) {
+      int argc;
+      pic_value *argv;
+
+      argc = pc->u.i;
+      argv = pic->sp - argc;
+      for (i = 0; i < argc; ++i) {
+	pic->ci->fp[i] = argv[i];
+      }
+      pic->sp = pic->ci->fp + argc;
+      pc = POPCI()->pc;
+
+      goto L_CALL;
+    }
     CASE(OP_RET) {
       pic_value v;
       pic_callinfo *ci;