Compatibility update to PPU, passes one more electronics test (Thanks MKendora!)

zsnes/src/cpu/execute.asm

@@ -104,7 +104,7 @@ EXTSYM JoyRead,ChatType2,chatstrR2,chatstrR3,chatstrR4,chatstrR5
 EXTSYM chatRTL2,chatRTL3,chatRTL4,chatRTL5
 EXTSYM NetLoadState
 EXTSYM ProcessMovies
-EXTSYM ioportval
+EXTSYM ioportval,ppustatus
 EXTSYM C4VBlank
 EXTSYM dsp1teststuff
 EXTSYM ReturnFromSPCStall,SPCStallSetting,cycpb268,cycpb358,HIRQSkip,scanlines
@@ -4563,6 +4563,7 @@ NEWSYM execsingle
 .overy
     shr dh,1
     mov word[curypos],0
+    xor byte[ppustatus],80h
     mov byte[NMIEnab],01h
     add dword[opcd],170*262
     call cachevideo

zsnes/src/cpu/regs.inc

@@ -409,6 +409,7 @@ NEWSYM nosprincr, db 0
 NEWSYM poamaddrs, dw 0
 NEWSYM ioportval, db 255
 NEWSYM iohvlatch, db 0
+NEWSYM ppustatus, db 0
 
 
 NEWSYM tempdat, times 478 db 0     ; expandable area
@@ -734,7 +735,8 @@ reg213Er:
 ; PPU Status Flag & Version number (NTSC/PAL/EXTRN Latch flag)
 reg213Fr:
 ;    mov byte[debstop3],1
-    mov al,[romispal]
+    mov al,[ppustatus]
+    or al,[romispal]
     shl al,4
     or al,[cfield]
     mov byte[latchxr],0