Add new Cheat Type F4, Find & Replace Bytes (#1345)

* Add new Cheat Type F4, Find & Replace Bytes

Also knows as 'AOB' apparently. Information about how it works will be in the next chtdb.txt header or you can read/ask about it on the discord channel.

* Add new Cheat Type F4, Find & Replace Bytes 

Also knows as 'AOB' apparently. Information about how it works will be in the next chtdb.txt header or you can read/ask about it on the discord channel.

* Added error trapping for cheat type F4

As suggested

src/core/cheats.cpp

@@ -1213,6 +1213,98 @@ void CheatCode::Apply() const
         index += 2;
       }
       break;
+      
+      case InstructionCode::ExtFindAndReplace:
+      {
+          
+        if ((index + 4) >= instructions.size())
+        {
+          Log_ErrorPrintf("Incomplete find/replace instruction");
+          return;
+        }
+        const Instruction& inst2 = instructions[index + 1];
+        const Instruction& inst3 = instructions[index + 2];
+        const Instruction& inst4 = instructions[index + 3];
+        const Instruction& inst5 = instructions[index + 4];   
+        
+        const u32 offset = Truncate16(inst.value32 & 0x0000FFFFu) << 1;
+        const u8 wildcard = Truncate8((inst.value32 & 0x00FF0000u) >> 16);
+        const u32 minaddress = inst.address - offset;
+        const u32 maxaddress = inst.address + offset;
+        const u8 f1  = Truncate8((inst2.first & 0xFF000000u) >> 24);
+        const u8 f2  = Truncate8((inst2.first & 0x00FF0000u) >> 16);
+        const u8 f3  = Truncate8((inst2.first & 0x0000FF00u) >> 8);
+        const u8 f4  = Truncate8 (inst2.first & 0x000000FFu);
+        const u8 f5  = Truncate8((inst2.value32 & 0xFF000000u) >> 24);
+        const u8 f6  = Truncate8((inst2.value32 & 0x00FF0000u) >> 16);
+        const u8 f7  = Truncate8((inst2.value32 & 0x0000FF00u) >> 8);
+        const u8 f8  = Truncate8 (inst2.value32 & 0x000000FFu);
+        const u8 f9  = Truncate8((inst3.first & 0xFF000000u) >> 24);
+        const u8 f10 = Truncate8((inst3.first & 0x00FF0000u) >> 16);
+        const u8 f11 = Truncate8((inst3.first & 0x0000FF00u) >> 8);
+        const u8 f12 = Truncate8 (inst3.first & 0x000000FFu);
+        const u8 f13 = Truncate8((inst3.value32 & 0xFF000000u) >> 24);
+        const u8 f14 = Truncate8((inst3.value32 & 0x00FF0000u) >> 16);
+        const u8 f15 = Truncate8((inst3.value32 & 0x0000FF00u) >> 8);
+        const u8 f16 = Truncate8 (inst3.value32 & 0x000000FFu);
+        const u8 r1  = Truncate8((inst4.first & 0xFF000000u) >> 24);
+        const u8 r2  = Truncate8((inst4.first & 0x00FF0000u) >> 16);
+        const u8 r3  = Truncate8((inst4.first & 0x0000FF00u) >> 8);
+        const u8 r4  = Truncate8 (inst4.first & 0x000000FFu);
+        const u8 r5  = Truncate8((inst4.value32 & 0xFF000000u) >> 24);
+        const u8 r6  = Truncate8((inst4.value32 & 0x00FF0000u) >> 16);
+        const u8 r7  = Truncate8((inst4.value32 & 0x0000FF00u) >> 8);
+        const u8 r8  = Truncate8 (inst4.value32 & 0x000000FFu);
+        const u8 r9  = Truncate8((inst5.first & 0xFF000000u) >> 24);
+        const u8 r10 = Truncate8((inst5.first & 0x00FF0000u) >> 16);
+        const u8 r11 = Truncate8((inst5.first & 0x0000FF00u) >> 8);
+        const u8 r12 = Truncate8 (inst5.first & 0x000000FFu);
+        const u8 r13 = Truncate8((inst5.value32 & 0xFF000000u) >> 24);
+        const u8 r14 = Truncate8((inst5.value32 & 0x00FF0000u) >> 16);
+        const u8 r15 = Truncate8((inst5.value32 & 0x0000FF00u) >> 8);
+        const u8 r16 = Truncate8 (inst5.value32 & 0x000000FFu);        
+        
+        for (u32 address = minaddress;address<=maxaddress;address+=2)
+        {
+          if ((DoMemoryRead<u8>(address   )==f1 || f1  == wildcard) &&
+              (DoMemoryRead<u8>(address+1 )==f2 || f2  == wildcard) &&
+              (DoMemoryRead<u8>(address+2 )==f3 || f3  == wildcard) &&
+              (DoMemoryRead<u8>(address+3 )==f4 || f4  == wildcard) &&
+              (DoMemoryRead<u8>(address+4 )==f5 || f5  == wildcard) &&
+              (DoMemoryRead<u8>(address+5 )==f6 || f6  == wildcard) &&
+              (DoMemoryRead<u8>(address+6 )==f7 || f7  == wildcard) &&
+              (DoMemoryRead<u8>(address+7 )==f8 || f8  == wildcard) &&
+              (DoMemoryRead<u8>(address+8 )==f9 || f9  == wildcard) &&
+              (DoMemoryRead<u8>(address+9 )==f10|| f10 == wildcard) &&
+              (DoMemoryRead<u8>(address+10)==f11|| f11 == wildcard) &&
+              (DoMemoryRead<u8>(address+11)==f12|| f12 == wildcard) &&
+              (DoMemoryRead<u8>(address+12)==f13|| f13 == wildcard) &&
+              (DoMemoryRead<u8>(address+13)==f14|| f14 == wildcard) &&
+              (DoMemoryRead<u8>(address+14)==f15|| f15 == wildcard) &&
+              (DoMemoryRead<u8>(address+15)==f16|| f16 == wildcard))           
+          {
+            if (r1  != wildcard) DoMemoryWrite<u8>(address   , r1 );
+            if (r2  != wildcard) DoMemoryWrite<u8>(address+1 , r2 );
+            if (r3  != wildcard) DoMemoryWrite<u8>(address+2 , r3 );
+            if (r4  != wildcard) DoMemoryWrite<u8>(address+3 , r4 );
+            if (r5  != wildcard) DoMemoryWrite<u8>(address+4 , r5 );
+            if (r6  != wildcard) DoMemoryWrite<u8>(address+5 , r6 );  
+            if (r7  != wildcard) DoMemoryWrite<u8>(address+6 , r7 );  
+            if (r8  != wildcard) DoMemoryWrite<u8>(address+7 , r8 );  
+            if (r9  != wildcard) DoMemoryWrite<u8>(address+8 , r9 );  
+            if (r10 != wildcard) DoMemoryWrite<u8>(address+9 , r10);  
+            if (r11 != wildcard) DoMemoryWrite<u8>(address+10, r11);  
+            if (r12 != wildcard) DoMemoryWrite<u8>(address+11, r12);  
+            if (r13 != wildcard) DoMemoryWrite<u8>(address+12, r13);  
+            if (r14 != wildcard) DoMemoryWrite<u8>(address+13, r14);  
+            if (r15 != wildcard) DoMemoryWrite<u8>(address+14, r15);  
+            if (r16 != wildcard) DoMemoryWrite<u8>(address+15, r16);
+            address=address+15; 
+          }            
+        }
+        index += 5;
+      }
+      break;
 
       case InstructionCode::CompareEqual16:
       {
@@ -1479,7 +1571,9 @@ void CheatCode::ApplyOnDisable() const
       case InstructionCode::MemoryCopy:
         index += 2;
         break;
-
+      case InstructionCode::ExtFindAndReplace:  
+      index += 5;
+        break;
       // for conditionals, we don't want to skip over in case it changed at some point
       case InstructionCode::ExtCompareEqual32:
       case InstructionCode::ExtCompareNotEqual32:

src/core/cheats.h

@@ -62,6 +62,7 @@ struct CheatCode
     ExtConstantForceRangeLimits16 = 0xF1,
     ExtConstantForceRangeRollRound16 = 0xF2,
     ExtConstantForceRange16 = 0xF3,
+    ExtFindAndReplace = 0xF4,
     ExtConstantBitSet8 = 0x31,
     ExtConstantBitClear8 = 0x32,
     ExtConstantBitSet16 = 0x81,