From 29223bb979d87be2623cf34f3500a011e183fc93 Mon Sep 17 00:00:00 2001
From: Michael Munday <munday@ca.ibm.com>
Date: Thu, 29 Dec 2016 11:10:18 -0500
Subject: [PATCH] Implement POW.

Allows use of the '^' operator, for example:

x = 2
y = 3
print(x ^ y) -- prints 8
---
 src/vm_s390x.dasc | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/vm_s390x.dasc b/src/vm_s390x.dasc
index f5055a40..99200bc6 100644
--- a/src/vm_s390x.dasc
+++ b/src/vm_s390x.dasc
@@ -2059,9 +2059,24 @@ static void build_ins(BuildCtx *ctx, BCOp op, int defop)
     |  j ->vmeta_arith_vvo
     break;
   case BC_POW:
-    |  stg r0, 0(r0)
-    |  stg r0, 0(r0)
+    |  ins_ABC
+    |  sllg RB, RB, 3(r0)
+    |  sllg RC, RC, 3(r0)
+    |  ld FARG1, 0(RB, BASE)
+    |  ld FARG2, 0(RC, BASE)
+    |  lg TMPR2, 0(RB, BASE)
+    |  checknumtp TMPR2, ->vmeta_arith_vvo
+    |  lg TMPR2, 0(RC, BASE)
+    |  checknumtp TMPR2, ->vmeta_arith_vvo
+    |  lgr RB, BASE // TODO: redundant, BASE is currently callee-saved.
+    |  brasl r14, extern pow	// double pow(double x, double y), result in f0.
+    |  llgc RA, PC_RA
+    |  lgr BASE, RB
+    |  sllg RA, RA, 3(r0)
+    |  std f0, 0(RA, BASE)
+    |  ins_next
     break;
+
   case BC_CAT:
     |  stg r0, 0(r0)
     |  stg r0, 0(r0)