code review and optimizations

[picodrive.git] / cpu / Cyclone / Ea.cpp

diff --git a/cpu/Cyclone/Ea.cpp b/cpu/Cyclone/Ea.cpp
index 642a42b..8b103c9 100644 (file)
--- a/cpu/Cyclone/Ea.cpp
+++ b/cpu/Cyclone/Ea.cpp
@@ -100,7 +100,7 @@ static int EaCalcReg(int r,int ea,int mask,int forceor,int shift,int noshift=0)
 \r
   if (ea>=8) needor=1; // Need to OR to access A0-7\r
 \r
-  if ((mask>>low)&8) if (ea&8) needor=0; // Ah - no we don't actually need to or, since the bit is high in r8\r
+  if (((mask&g_op)>>low)&8) needor=0; // Ah - no we don't actually need to or, since the bit is high in r8\r
 \r
   if (forceor) needor=1; // Special case for 0x30-0x38 EAs ;)\r
 \r
@@ -121,8 +121,9 @@ static int EaCalcReg(int r,int ea,int mask,int forceor,int shift,int noshift=0)
 }\r
 \r
 // EaCalc - ARM Register 'a' = Effective Address\r
-// Trashes r0,r2 and r3\r
+// If ea>=0x10, trashes r0,r2 and r3, else nothing\r
 // size values 0, 1, 2 ~ byte, word, long\r
+// mask shows usable bits in r8\r
 int EaCalc(int a,int mask,int ea,int size,int top,int sign_extend)\r
 {\r
   char text[32]="";\r
@@ -151,12 +152,19 @@ int EaCalc(int a,int mask,int ea,int size,int top,int sign_extend)
 \r
     if ((ea&7)==7 && step<2) step=2; // move.b (a7)+ or -(a7) steps by 2 not 1\r
 \r
-    EaCalcReg(2,ea,mask,0,0,1);\r
-    if(mask)\r
-      for (i=mask|0x8000; (i&1)==0; i>>=1) low++; // Find out how high up the EA mask is\r
-    lsl=2-low; // Having a lsl #x here saves one opcode\r
-    if      (lsl>=0) ot("  ldr r%d,[r7,r2,lsl #%i]\n",a,lsl);\r
-    else if (lsl<0)  ot("  ldr r%d,[r7,r2,lsr #%i]\n",a,-lsl);\r
+    if (ea==0x1f||ea==0x27) // A7 handlers are always separate\r
+    {\r
+      ot("  ldr r%d,[r7,#0x3c] ;@ A7\n",a);\r
+    }\r
+    else\r
+    {\r
+      EaCalcReg(2,ea,mask,0,0,1);\r
+      if(mask)\r
+        for (i=mask|0x8000; (i&1)==0; i>>=1) low++; // Find out how high up the EA mask is\r
+      lsl=2-low; // Having a lsl #x here saves one opcode\r
+      if      (lsl>=0) ot("  ldr r%d,[r7,r2,lsl #%i]\n",a,lsl);\r
+      else if (lsl<0)  ot("  ldr r%d,[r7,r2,lsr #%i]\n",a,-lsl);\r
+    }\r
 \r
     if ((ea&0x38)==0x18) // (An)+\r
     {\r
@@ -169,8 +177,15 @@ int EaCalc(int a,int mask,int ea,int size,int top,int sign_extend)
 \r
     if ((ea&0x38)==0x18||(ea&0x38)==0x20)\r
     {\r
-      if      (lsl>=0) ot("  str r%d,[r7,r2,lsl #%i]\n",strr,lsl);\r
-      else if (lsl<0)  ot("  str r%d,[r7,r2,lsr #%i]\n",strr,-lsl);\r
+      if (ea==0x1f||ea==0x27)\r
+      {\r
+        ot("  str r%d,[r7,#0x3c] ;@ A7\n",strr);\r
+      }\r
+      else\r
+      {\r
+        if      (lsl>=0) ot("  str r%d,[r7,r2,lsl #%i]\n",strr,lsl);\r
+        else if (lsl<0)  ot("  str r%d,[r7,r2,lsr #%i]\n",strr,-lsl);\r
+      }\r
     }\r
 \r
     if ((ea&0x38)==0x20) Cycles+=size<2 ? 6:10; // -(An) Extra cycles\r
@@ -263,8 +278,8 @@ int EaCalc(int a,int mask,int ea,int size,int top,int sign_extend)
     }\r
 \r
     ot("  ldrh r2,[r4],#2 ;@ Fetch immediate value\n");\r
-    ot("  ldrh r0,[r4],#2\n"); pc_dirty=1;\r
-    ot("  orr r%d,r0,r2,lsl #16\n",a);\r
+    ot("  ldrh r3,[r4],#2\n"); pc_dirty=1;\r
+    ot("  orr r%d,r3,r2,lsl #16\n",a);\r
     Cycles+=8; // Extra cycles\r
     return 0;\r
   }\r
@@ -298,7 +313,7 @@ int EaRead(int a,int v,int ea,int size,int mask,int top,int sign_extend)
       lsl=2-low; // Having a lsl #2 here saves one opcode\r
     }\r
 \r
-    if (top) nsarm=3;\r
+    if (top||!sign_extend) nsarm=3;\r
 \r
     ot(";@ EaRead : Read register[r%d] into r%d:\n",a,v);\r
 \r
@@ -352,6 +367,43 @@ int EaRead(int a,int v,int ea,int size,int mask,int top,int sign_extend)
   ot("\n"); return 0;\r
 }\r
 \r
+// calculate EA and  read\r
+// if (ea  < 0x10) nothing is trashed\r
+// if (ea == 0x3c) r2 and r3 are trashed\r
+// else r0-r3 are trashed\r
+// size values 0, 1, 2 ~ byte, word, long\r
+// r_ea is reg to store ea in (-1 means ea is not needed), r is dst reg\r
+// if sign_extend is 0, non-32bit values will have MS bits undefined\r
+int EaCalcRead(int r_ea,int r,int ea,int size,int mask,int sign_extend)\r
+{\r
+  if (ea<0x10)\r
+  {\r
+    if (r_ea==-1)\r
+    {\r
+      r_ea=r;\r
+      if (!sign_extend) size=2;\r
+    }\r
+  }\r
+  else if (ea==0x3c) // #imm\r
+  {\r
+    r_ea=r;\r
+  }\r
+  else\r
+  {\r
+    if (r_ea==-1) r_ea=0;\r
+  }\r
+\r
+  EaCalc (r_ea,mask,ea,size,0,sign_extend);\r
+  EaRead (r_ea,   r,ea,size,mask,0,sign_extend);\r
+\r
+  return 0;\r
+}\r
+\r
+int EaCalcReadNoSE(int r_ea,int r,int ea,int size,int mask)\r
+{\r
+  return EaCalcRead(r_ea,r,ea,size,mask,0);\r
+}\r
+\r
 // Return 1 if we can read this ea\r
 int EaCanRead(int ea,int size)\r
 {\r