INES Mapper 164: Difference between revisions
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======================== | ======================== | ||
Example | Example Games: | ||
-------------------------- | -------------------------- | ||
Final Fantasy V | Final Fantasy V | ||
Pokémon Red [宠物红](Waixing) | |||
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Swapping is really simple -- the thing that is funky is the register range/mask. $5000 and $D000 will access | Swapping is really simple -- the thing that is funky is the register range/mask. $5000 and $D000 will access | ||
the register, however $5100, $5200, etc will not. | the register, however $5100, $5200, etc will not. | ||
FCEUX implements mapper 164 as: | FCEUX implements mapper 164 as: | ||
$5000: [.... LLLL] | |||
$5100: [.... HHHH] | |||
$5300: 8-bit latch | |||
Writing to either $5000 or $5100 immediately switches a 32kB or 512kB chunk. | Writing to either $5000 or $5100 immediately switches a 32kB or 512kB chunk. | ||
Reading from $5100 or $5900 returns the value of the latch, but not $5500 or $5D00 | Reading from $5100 or $5900 returns the value of the latch, but not $5500 or $5D00 | ||
Nestopia implements mapper 164 as: | Nestopia implements mapper 164 as: | ||
$5000: [.ABC DLLL] | |||
$5100: [.... ...H] | |||
Writing to either immediately switches banks. The interpretation of the address depends on ABC: | Writing to either immediately switches banks. The interpretation of the address depends on ABC: | ||
C=0: Switch 16kB at $8000, address specified by HBDLLL; 16kB at $C000 switched to H11111. | |||
A=0 C=1: undefined (noop) | |||
ABC=5: Switch 32kB at $8000, address specified by HDLLL | |||
ABC=7: Switch 16kB at $8000, address specified by HDDLLL; 16kB at $C000 switched to H11111. (Yes, D appears twice) | |||
Note that the copy of Final Fantasy V in GoodNES does not work correctly in Nestopia. This should ''not'' be taken as an indication that Nestopia's implementation is necessarily wrong. | Note that the copy of Final Fantasy V in GoodNES does not work correctly in Nestopia. This should ''not'' be taken as an indication that Nestopia's implementation is necessarily wrong. | ||
Revision as of 18:08, 14 March 2015
These notes are not very good. There is more information to be got. Check some emulator sources and please elaborate here.
Here are Disch's original notes:
========================
= Mapper 164 =
========================
Example Games:
--------------------------
Final Fantasy V
Pokémon Red [宠物红](Waixing)
Registers:
---------------------------
Range,Mask: $5000-FFFF, $F300
$5000, $D000: PRG reg (32k @ $8000)
$6000-7FFF may have SRAM (not sure)
On Reset
---------------------------
Reg seems to contain $FF on powerup/reset
Notes:
---------------------------
Swapping is really simple -- the thing that is funky is the register range/mask. $5000 and $D000 will access
the register, however $5100, $5200, etc will not.
FCEUX implements mapper 164 as:
$5000: [.... LLLL]
$5100: [.... HHHH]
$5300: 8-bit latch
Writing to either $5000 or $5100 immediately switches a 32kB or 512kB chunk.
Reading from $5100 or $5900 returns the value of the latch, but not $5500 or $5D00
Nestopia implements mapper 164 as:
$5000: [.ABC DLLL]
$5100: [.... ...H]
Writing to either immediately switches banks. The interpretation of the address depends on ABC:
C=0: Switch 16kB at $8000, address specified by HBDLLL; 16kB at $C000 switched to H11111.
A=0 C=1: undefined (noop)
ABC=5: Switch 32kB at $8000, address specified by HDLLL
ABC=7: Switch 16kB at $8000, address specified by HDDLLL; 16kB at $C000 switched to H11111. (Yes, D appears twice)
Note that the copy of Final Fantasy V in GoodNES does not work correctly in Nestopia. This should not be taken as an indication that Nestopia's implementation is necessarily wrong.
