From c5453432f390b06866000604176e240a16701f09 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Remko=20Tron=C3=A7on?= <remko@el-tramo.be>
Date: Fri, 1 Jun 2018 23:05:28 +0200
Subject: [PATCH] Implement */MOD

---
 src/waforth.wat | 17 +++++++++++++++++
 tests/index.js  | 19 +++++++++++++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/src/waforth.wat b/src/waforth.wat
index 9a1d000..3964857 100644
--- a/src/waforth.wat
+++ b/src/waforth.wat
@@ -194,6 +194,23 @@
     (set_global $tos (get_local $bbtos)))
   (!def_word "*/" "$*/")
 
+  ;; 6.1.0110
+  (func $*/MOD (param i32)
+    (local $btos i32)
+    (local $bbtos i32)
+    (local $bbbtos i32)
+    (local $x1 i64)
+    (local $x2 i64)
+    (i32.store (tee_local $bbbtos (i32.sub (get_global $tos) (i32.const 12)))
+               (i32.wrap/i64
+                  (i64.rem_s
+                      (tee_local $x1 (i64.mul (i64.extend_s/i32 (i32.load (get_local $bbbtos)))
+                                              (i64.extend_s/i32 (i32.load (tee_local $bbtos (i32.sub (get_global $tos) (i32.const 8)))))))
+                      (tee_local $x2 (i64.extend_s/i32 (i32.load (tee_local $btos (i32.sub (get_global $tos) (i32.const 4)))))))))
+    (i32.store (get_local $bbtos) (i32.wrap/i64 (i64.div_s (get_local $x1) (get_local $x2))))
+    (set_global $tos (get_local $btos)))
+  (!def_word "*/MOD" "$*/MOD")
+
   ;; 6.1.0120
   (func $plus (param i32)
     (local $btos i32)
diff --git a/tests/index.js b/tests/index.js
index 8a5bf8e..e015eb3 100644
--- a/tests/index.js
+++ b/tests/index.js
@@ -306,6 +306,21 @@ describe("WAForth", () => {
     });
   });
 
+  describe("*/MOD", () => {
+    it("should work with small numbers", () => {
+      run("9 3 5 */MOD 7");
+      expect(stack[0]).to.eql(2);
+      expect(stack[1]).to.eql(5);
+      expect(stack[2]).to.eql(7);
+    });
+
+    it("should work with large numbers", () => {
+      run("268435455 1000 3333 */MOD");
+      expect(stack[0]).to.eql(1230);
+      expect(stack[1]).to.eql(80538690);
+    });
+  });
+
   describe("1+", () => {
     it("should work with positive numbers", () => {
       run("3");
@@ -796,7 +811,7 @@ describe("WAForth", () => {
       forth.read("DUP");
       core.WORD();
       core.FIND();
-      expect(stack[0]).to.eql(131740);
+      expect(stack[0]).to.eql(131756);
       expect(stack[1]).to.eql(-1);
     });
 
@@ -812,7 +827,7 @@ describe("WAForth", () => {
       forth.read("+LOOP");
       core.WORD();
       core.FIND();
-      expect(stack[0]).to.eql(131144);
+      expect(stack[0]).to.eql(131160);
       expect(stack[1]).to.eql(1);
     });