From 198817609e33a09e825e71e85118d1b07ecdf645 Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Mon, 6 Oct 2014 02:49:56 +0300
Subject: [PATCH] support a few ARMv6 instructions

---
 Ea.cpp    |  6 ++----
 Makefile  |  3 +++
 OpAny.cpp | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 app.h     |  2 ++
 config.h  | 10 ++++++++++
 5 files changed, 63 insertions(+), 4 deletions(-)

diff --git a/Ea.cpp b/Ea.cpp
index fc4dff9..5969529 100644
--- a/Ea.cpp
+++ b/Ea.cpp
@@ -372,8 +372,7 @@ int EaRead(int a,int v,int ea,int size,int mask,EaRWType type,int set_nz)
   {
     int d_reg=0;
     if (shift) {
-      ot("  mov r%d,r%d,asl #%d\n",v,d_reg,shift);
-      ot("  mov%s r%d,r%d,asr #%d\n",s,v,v,shift);
+      SignExtend(v, d_reg, size);
       d_reg=v;
       flags_set=1;
     }
@@ -498,8 +497,7 @@ int EaWrite(int a,int v,int ea,int size,int mask,EaRWType type)
     case 1:
       if (type != earwt_zero_extend)
       {
-        ot("  mov r1,r%d,lsl #16\n",v);
-        ot("  mov r1,r1,lsr #16\n");
+        ZeroExtend(1, v, size);
         break;
       }
       // fallthrough
diff --git a/Makefile b/Makefile
index 8b7a5fd..98a578a 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,9 @@ CFLAGS += -Wall -ggdb
 ifdef CONFIG_FILE
 CFLAGS += -DCONFIG_FILE="\"$(CONFIG_FILE)\""
 endif
+ifdef HAVE_ARMv6
+CFLAGS += -DHAVE_ARMv6=$(HAVE_ARMv6)
+endif
 CXXFLAGS += $(CFLAGS)
 
 OBJS = Main.o Ea.o OpAny.o OpArith.o OpBranch.o OpLogic.o OpMove.o Disa/Disa.o
diff --git a/OpAny.cpp b/OpAny.cpp
index 8cb8c09..64e2bfe 100644
--- a/OpAny.cpp
+++ b/OpAny.cpp
@@ -165,6 +165,52 @@ void OpGetFlagsNZ(int rd)
   ot("  orreq r10,r10,#0x40000000 ;@ get NZ, clear CV\n");
 }
 
+// size 0=8bit, 1=16bit
+void SignExtend(int rd, int rs, int size)
+{
+  if (size >= 2)
+  {
+    if (rd != rs)
+      ot("  mov r%d,r%d\n", rd, rs);
+    return;
+  }
+#if defined(HAVE_ARMv6) && (HAVE_ARMv6)
+  if (size == 1)
+    ot("  sxth r%d,r%d ;@ sign extend\n", rd, rs);
+  else
+    ot("  sxtb r%d,r%d ;@ sign extend\n", rd, rs);
+#else
+  int shift = size ? 16 : 24;
+  ot("  mov r%d,r%d,asl #%d\n", rd, rs, shift);
+  ot("  mov r%d,r%d,asr #%d ;@ sign extend\n", rd, rd, shift);
+#endif
+}
+
+void ZeroExtend(int rd, int rs, int size)
+{
+  if (size >= 2)
+  {
+    if (rd != rs)
+      ot("  mov r%d,r%d\n", rd, rs);
+    return;
+  }
+#if defined(HAVE_ARMv6) && (HAVE_ARMv6)
+  if (size == 1)
+    ot("  uxth r%d,r%d ;@ zero extend\n", rd, rs);
+  else
+#else
+  if (size == 1)
+  {
+    ot("  mov r%d,r%d,lsl #16\n", rd, rs);
+    ot("  mov r%d,r%d,lsr #16 ;@ zero extend\n", rd, rd);
+  }
+  else
+#endif
+  {
+    ot("  and r%d,r%d,#0xff ;@ zero extend\n", rd, rs);
+  }
+}
+
 // -----------------------------------------------------------------
 
 int g_op;
diff --git a/app.h b/app.h
index cffd2cb..9d01957 100644
--- a/app.h
+++ b/app.h
@@ -65,6 +65,8 @@ extern int g_op;
 extern int opend_op_changes_cycles, opend_check_interrupt, opend_check_trace;
 int OpGetFlags(int subtract,int xbit,int sprecialz=0);
 void OpGetFlagsNZ(int rd);
+void SignExtend(int rd, int rs, int size);
+void ZeroExtend(int rd, int rs, int size);
 void OpUse(int op,int use);
 void OpStart(int op,int sea=0,int tea=0,int op_changes_cycles=0,int supervisor_check=0);
 void OpEnd(int sea=0,int tea=0);
diff --git a/config.h b/config.h
index d73b5b5..86bd6e0 100644
--- a/config.h
+++ b/config.h
@@ -5,6 +5,16 @@
 **/
 
 
+/*
+ * By default, only ARMv4 instructions are used.
+ * If you want Cyclone to make use of newer ARM instructions, enable the
+ * options(s) below. You can also override this using make argument:
+ *   make HAVE_ARMv6=1
+ */
+#ifndef HAVE_ARMv6
+#define HAVE_ARMv6                  0
+#endif
+
 /*
  * If this option is enabled, Microsoft ARMASM compatible output is generated
  * (output file -  Cyclone.asm). Otherwise GNU as syntax is used (Cyclone.s).
-- 
2.39.2