don't pass trash in MSB bits to write8 and write16 handlers

otherwise it effectively breaks the C ABI

diff --git a/Ea.cpp b/Ea.cpp
index effd4c2..fc4dff9 100644 (file)
--- a/Ea.cpp
+++ b/Ea.cpp
@@ -338,7 +338,7 @@ int EaRead(int a,int v,int ea,int size,int mask,EaRWType type,int set_nz)
 \r
     if      (lsl>0) ot("  ldr%s r%d,[r7,r%d,lsl #%i]\n",Narm[nsarm],v,a,lsl);\r
     else if (lsl<0) ot("  ldr%s r%d,[r7,r%d,lsr #%i]\n",Narm[nsarm],v,a,-lsl);\r
-    else            ot("  ldr%s r%d,[r7,r%d]\n",Sarm[nsarm],v,a);\r
+    else            ot("  ldr%s r%d,[r7,r%d]\n",type==earwt_sign_extend?Sarm[nsarm]:Narm[nsarm],v,a);\r
 \r
     if (type == earwt_shifted_up && shift)\r
       ot("  mov%s r%d,r%d,asl #%d\n",s,v,v,shift);\r
@@ -472,7 +472,7 @@ int EaWrite(int a,int v,int ea,int size,int mask,EaRWType type)
     }\r
 \r
     ot(";@ EaWrite: r%d into register[r%d]:\n",v,a);\r
-    if (shift)  ot("  mov r%d,r%d,asr #%d\n",v,v,shift);\r
+    if (shift)  ot("  mov r%d,r%d,lsr #%d\n",v,v,shift);\r
 \r
     if      (lsl>0) ot("  str%s r%d,[r7,r%d,lsl #%i]\n",Narm[size&3],v,a,lsl);\r
     else if (lsl<0) ot("  str%s r%d,[r7,r%d,lsr #%i]\n",Narm[size&3],v,a,-lsl);\r
@@ -485,8 +485,30 @@ int EaWrite(int a,int v,int ea,int size,int mask,EaRWType type)
 \r
   if (ea==0x3c) { ot("Error! Write EA=0x%x\n\n",ea); return 1; }\r
 \r
-  if (shift)     ot("  mov r1,r%d,asr #%d\n",v,shift);\r
-  else if (v!=1) ot("  mov r1,r%d\n",v);\r
+  if (shift)\r
+  {\r
+    ot("  mov r1,r%d,lsr #%d\n",v,shift);\r
+  }\r
+  else if (v != 1 || (size < 2 && type != earwt_zero_extend))\r
+  {\r
+    switch (size) {\r
+    case 0:\r
+      ot("  and r1,r%d,#0xff\n",v);\r
+      break;\r
+    case 1:\r
+      if (type != earwt_zero_extend)\r
+      {\r
+        ot("  mov r1,r%d,lsl #16\n",v);\r
+        ot("  mov r1,r1,lsr #16\n");\r
+        break;\r
+      }\r
+      // fallthrough\r
+    case 2:\r
+    default:\r
+      ot("  mov r1,r%d\n",v);\r
+      break;\r
+    }\r
+  }\r
 \r
   MemHandler(1,size,a,eawrite_check_addrerr); // Call write handler\r
 \r

diff --git a/OpMove.cpp b/OpMove.cpp
index 3d893de..44842ee 100644 (file)
--- a/OpMove.cpp
+++ b/OpMove.cpp
@@ -96,6 +96,7 @@ void SuperChange(int op,int srh_reg)
 // Emit a Move opcode, 00xxdddd ddssssss\r
 int OpMove(int op)\r
 {\r
+  EaRWType eatype;\r
   int sea=0,tea=0;\r
   int size=0,use=0;\r
   int movea=0;\r
@@ -133,13 +134,25 @@ int OpMove(int op)
 \r
   if (movea==0)\r
   {\r
-    EaCalcRead(-1,1,sea,size,0x003f,earwt_sign_extend,1);\r
-    OpGetFlagsNZ(1);\r
+    if (sea < 0x10 && size < 2)\r
+    {\r
+      eatype = earwt_zero_extend;\r
+      EaCalcRead(-1,1,sea,size,0x003f,eatype);\r
+      ot("  movs r2,r1,lsl #%d\n",size?16:24);\r
+      OpGetFlagsNZ(2);\r
+    }\r
+    else\r
+    {\r
+      eatype = earwt_shifted_up;\r
+      EaCalcRead(-1,1,sea,size,0x003f,eatype,1);\r
+      OpGetFlagsNZ(1);\r
+    }\r
     ot("\n");\r
   }\r
   else\r
   {\r
-    EaCalcRead(-1,1,sea,size,0x003f,earwt_sign_extend);\r
+    eatype = earwt_sign_extend;\r
+    EaCalcRead(-1,1,sea,size,0x003f,eatype);\r
     size=2; // movea always expands to 32-bits\r
   }\r
 \r
@@ -155,8 +168,8 @@ int OpMove(int op)
   else\r
 #endif\r
   {\r
-    EaCalc (0,0x0e00,tea,size,earwt_msb_dont_care);\r
-    EaWrite(0,     1,tea,size,0x0e00,earwt_msb_dont_care);\r
+    EaCalc (0,0x0e00,tea,size,eatype);\r
+    EaWrite(0,     1,tea,size,0x0e00,eatype);\r
   }\r
 \r
 #if CYCLONE_FOR_GENESIS && !MEMHANDLERS_CHANGE_CYCLES\r