fix instructions in README and fix ROM builder script to work for eit…

…her LoRAM or HiRAM configurations

README

@@ -80,12 +80,12 @@ RAM in the high space, do the following:
    - In the code block following the comment "decompress Splash screen":
      - change the instruction: "LDI  $C9" to: "LDI  $49"
      - change the instruction: "ADCI $C9" to: "ADCI $49"
-     - change the *second* instruction like "LDI  $00" to: "LDI  $80"
+     - change the instruction: "LDI  $00" to: "LDI  $80"
      - change the instruction: "ADCI $00" to: "ADCI $80"
    - In the code block following the comment "print the splash screen":
      - change the instruction: "LDI  $00" to: "LDI  $80"
    - In the code block following the comment "decompress Adventureland program":
-     - change the *first* instruction like "LDI  $00" to: "LDI  $80"
+     - change the instruction: "LDI  $00" to: "LDI  $80"
      - change the instruction: "ADCI $00" to: "ADCI $80"
    - In the code block following the "Exit" label:
      - change the instruction: "LDI  $8B" to: "LDI  $0B"

build_rom.py

@@ -38,15 +38,16 @@
     if ord(binData[0]) != 0xC0:
         print("Invalid game core binary: missing starting LBR")
         sys.exit(1)
-    sizeProgram = ord(binData[1]) * 256 + ord(binData[2]) - 0x10
+    endProgram = ord(binData[1]) * 256 + ord(binData[2])
+    sizeProgram = (endProgram & 0x7FFF) - 0x10
     if sizeProgram + 3 > len(binData):
         print("Invalid game core binary: file data length %i is less than required program size %i" % (len(binData), sizeProgram + 3))
         sys.exit(1)
     if ord(binData[sizeProgram]) != 0xC0:
         print("Invalid game core binary: missing ending LBR")
         sys.exit(1)
     addrGameStart = ord(binData[sizeProgram+1]) * 256 + ord(binData[sizeProgram+2])
-    if addrGameStart < 0x10 or addrGameStart >= sizeProgram + 0x10:
+    if (addrGameStart & 0x7FFF) < 0x10 or (addrGameStart & 0x7FFF) >= sizeProgram + 0x10:
         print("Invalid game core binary: game start address %x is invalid" % addrGameStart)
         sys.exit(1)
     binData = binData[3:sizeProgram]