Fix compilation with current Nim version

Author: def-

src/nes/mapper1.nim

@@ -3,7 +3,7 @@ import types
 type Mapper1* = ref object of Mapper
   cartridge: Cartridge
   shiftRegister, control, prgMode, chrMode, prgBank, chrBank0, chrBank1: uint8
-  prgOffsets, chrOffsets: array[0'u8..1'u8, int]
+  prgOffsets, chrOffsets: array[0..1, int]
 
 proc prgBankOffset(m: Mapper1, index: int): int =
   var index = if index >= 0x80: index - 0x100 else: index
@@ -24,11 +24,12 @@ proc writeControl(m: Mapper1, val: uint8) =
   m.chrMode = (val shr 4) and 1
   m.prgMode = (val shr 2) and 3
 
-  m.cartridge.mirror = uint8(case val and 3
-  of 0: mirrorSingle0
-  of 1: mirrorSingle1
-  of 2: mirrorVertical
-  of 3: mirrorHorizontal)
+  case val and 3
+  of 0: m.cartridge.mirror = mirrorSingle0.uint8
+  of 1: m.cartridge.mirror = mirrorSingle1.uint8
+  of 2: m.cartridge.mirror = mirrorVertical.uint8
+  of 3: m.cartridge.mirror = mirrorHorizontal.uint8
+  else: discard
 
 proc updateOffsets(m: Mapper1) =
   case m.prgMode

src/nes/mapper4.nim

@@ -4,9 +4,9 @@ type Mapper4* = ref object of Mapper
   cartridge: Cartridge
   nes: NES
   register, prgMode, chrMode, reload, counter: uint8
-  registers: array[0'u8..7'u8, uint8]
-  prgOffsets: array[0'u8..3'u8, int]
-  chrOffsets: array[0'u8..7'u8, int]
+  registers: array[0..7, uint8]
+  prgOffsets: array[0..3, int]
+  chrOffsets: array[0..7, int]
   irqEnable: bool
 
 proc prgBankOffset(m: Mapper4, index: int): int =
@@ -64,9 +64,10 @@ proc writeBankSelect(m: Mapper4, val: uint8) =
   m.register = val and 7
 
 proc writeMirror(m: Mapper4, val: uint8) =
-  m.cartridge.mirror = uint8(case val and 1
-  of 0: mirrorVertical
-  of 1: mirrorHorizontal)
+  case val and 1
+  of 0: m.cartridge.mirror = mirrorVertical.uint8
+  of 1: m.cartridge.mirror = mirrorHorizontal.uint8
+  else: discard
 
 proc writeRegister(m: Mapper4, adr: uint16, val: uint8) =
   case adr

src/nes/types.nim

@@ -155,7 +155,7 @@ type
 
   Cartridge* = ref object
     prg*, chr*: seq[uint8]
-    sram*: array[0x2000'u16, uint8]
+    sram*: array[0x2000, uint8]
     mapper*, mirror*: uint8
     battery*: bool