add condition to reset mmc1 macro, add constant

Author: zohassadar

src/io.asm

@@ -45,6 +45,7 @@ KB_MASK  := $1E
 MMC1_Control := $8000
 MMC1_CHR0   := $BFFF
 MMC1_CHR1   := $DFFF
+MMC1_PRG    := $FFFF
 
 MMC3_BANK_SELECT := $8000
 MMC3_BANK_DATA := $8001
@@ -61,7 +62,7 @@ MMC5_CHR_BANK0 := $5123 ; 4kb page index
 MMC5_CHR_BANK1 := $5127
 
 .macro RESET_MMC1
-.if INES_MAPPER = 1
+.if INES_MAPPER = 0 .or INES_MAPPER = 1
 :       inc :-  ; increments inc ($aa), writing a negative value to prg
                 ; https://www.nesdev.org/wiki/MMC1#Reset
 .endif

src/reset.asm

@@ -55,9 +55,11 @@ mapperInit:
 ; autodetect
 .if INES_MAPPER = 0
         setMMC1PRG ; initialize mmc1 just in case
+        ; cnrom can pass one of these tests but not both.
+        ; Start with the one it's supposed to fail.
         jsr testVerticalMirroring
-        bne not_mmc1 ; cnrom should bail here
-        jsr testHorizontalMirroring ; Test again in case of cnrom miswire
+        bne not_mmc1
+        jsr testHorizontalMirroring
         bne not_mmc1
         inc mapperId ; 1 for MMC1, otherwise 0 for CNROM
 not_mmc1:
@@ -99,9 +101,3 @@ not_mmc1:
         stx MMC5_RAM_PROTECT1 ; 2: enable PRG RAM
 .endif
         rts
-
-
-MMC1_PRG:
-        .byte   $00,$00,$00,$00,$00,$00,$00,$00
-        .byte   $00
-        .byte   $00