From 86cc6e6159412c25349c93ee42a8aa5c5324b915 Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Sun, 22 May 2022 12:54:32 +0200
Subject: [PATCH] vvp: Remove unused `%cmp/ws` and `%cmp/wu` instructions

The `%cmp/ws` and `%cmp/wu` instructions compare two index registers. They
are currently unused. Since the index registers are not used for data there
is not really a need to compare them. Values can be compared before loading
them into an index register.

So remove these two instructions.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
---
 vvp/compile.cc  |  2 --
 vvp/opcodes.txt |  5 -----
 vvp/vthread.cc  | 28 ----------------------------
 3 files changed, 35 deletions(-)

diff --git a/vvp/compile.cc b/vvp/compile.cc
index a131658cc..46ec619d0 100644
--- a/vvp/compile.cc
+++ b/vvp/compile.cc
@@ -129,8 +129,6 @@ static const struct opcode_table_s opcode_table[] = {
       { "%cmp/we",  of_CMPWE,  0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%cmp/wne", of_CMPWNE, 0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%cmp/wr",  of_CMPWR,  0,  {OA_NONE,     OA_NONE,     OA_NONE} },
-      { "%cmp/ws",  of_CMPWS,  2,  {OA_BIT1,     OA_BIT2,     OA_NONE} },
-      { "%cmp/wu",  of_CMPWU,  2,  {OA_BIT1,     OA_BIT2,     OA_NONE} },
       { "%cmp/x",   of_CMPX,   0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%cmp/z",   of_CMPZ,   0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%cmpi/e",  of_CMPIE,  3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
diff --git a/vvp/opcodes.txt b/vvp/opcodes.txt
index 461ba89f1..44414b080 100644
--- a/vvp/opcodes.txt
+++ b/vvp/opcodes.txt
@@ -341,11 +341,6 @@ values from the real-value stack and writes the comparison result to
 bits 4/5. The expressions (a < b) and (a==b) are calculated, with (b)
 popped from the stack first, then (a).
 
-* %cmp/ws <bit-l>, <bit-r>
-* %cmp/wu <bit-l>, <bit-r>
-
-[compare signed/unsigned integer words.]
-
 * %cmp/z
 * %cmp/x
 
diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index 6b797379f..ac09ff96c 100644
--- a/vvp/vthread.cc
+++ b/vvp/vthread.cc
@@ -2245,34 +2245,6 @@ bool of_CMPWR(vthread_t thr, vvp_code_t)
       return true;
 }
 
-bool of_CMPWS(vthread_t thr, vvp_code_t cp)
-{
-      int64_t l = thr->words[cp->bit_idx[0]].w_int;
-      int64_t r = thr->words[cp->bit_idx[1]].w_int;
-
-      vvp_bit4_t eq = (l == r)? BIT4_1 : BIT4_0;
-      vvp_bit4_t lt = (l <  r)? BIT4_1 : BIT4_0;
-
-      thr->flags[4] = eq;
-      thr->flags[5] = lt;
-
-      return true;
-}
-
-bool of_CMPWU(vthread_t thr, vvp_code_t cp)
-{
-      uint64_t l = thr->words[cp->bit_idx[0]].w_uint;
-      uint64_t r = thr->words[cp->bit_idx[1]].w_uint;
-
-      vvp_bit4_t eq = (l == r)? BIT4_1 : BIT4_0;
-      vvp_bit4_t lt = (l <  r)? BIT4_1 : BIT4_0;
-
-      thr->flags[4] = eq;
-      thr->flags[5] = lt;
-
-      return true;
-}
-
 /*
  * %cmp/z
  */