Proper behaviour of RDIO regs

zsnes/src/cpu/regs.inc

@@ -664,9 +664,10 @@ NEWSYM SDD1BankD, db 3
 NEWSYM vramread2, db 0             ; previous character for vram read
 NEWSYM nosprincr, db 0
 NEWSYM poamaddrs, dw 0
+NEWSYM rdioval, db 0
 
 
-NEWSYM tempdat, times 480 db 0     ; expandable area
+NEWSYM tempdat, times 479 db 0     ; expandable area
 
 num2writeppureg equ $-sndrot
 ; pharos equ hack *sigh*
@@ -1371,9 +1372,7 @@ debblah2:
 
 ; Programmable I/O port
 reg4213r:
-;    mov al,[mode7A]
-;    xor al,al
-;    mov al,0FFh
+    mov al,[rdioval]
     ret
 
 ; Quotent of Divide Result (Low)