ROM Addressing - Revision history

Megmactv at 07:25, 15 April 2021

2021-04-15T07:25:56Z

Megmactv: /* ROM File */

2021-04-15T07:25:19Z

ROM File

Megmactv: /* Bank And Memory Address */

2021-04-15T07:19:32Z

Bank And Memory Address

Megmactv: /* Memory */

2021-04-15T07:18:35Z

Memory

Megmactv at 06:24, 15 April 2021

2021-04-15T06:24:07Z

Megmactv at 06:23, 15 April 2021

2021-04-15T06:23:33Z

Megmactv: /* ROM File */

2021-04-15T06:16:20Z

ROM File

Megmactv at 06:11, 15 April 2021

2021-04-15T06:11:48Z

Megmactv at 05:32, 15 April 2021

2021-04-15T05:32:06Z

Megmactv: Created page with "There are several different ways to refer to data in memory in Zelda II. Which one you use depends on your reasoning for doing so. This page will explain where they're useful..."

2021-04-15T05:31:46Z

Created page with "There are several different ways to refer to data in memory in Zelda II. Which one you use depends on your reasoning for doing so. This page will explain where they're useful..."

New page

There are several different ways to refer to data in memory in Zelda II. Which one you use depends on your reasoning for doing so. This page will explain where they're useful and how to translate between them.

=Memory Addresses=

==CPU Address==

==Bank And Offset==

=ROM File Addresses=

← Older revision		Revision as of 07:25, 15 April 2021
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	Unfortunately, this format is more complicated to convert into ROM file offsets, or vice versa, because you have to know more about how the game maps memory. For Zelda II in particular, the formula for converting to a dumped ROM offset is 0x10+(bank*0x4000)+(address%0x4000) -- where % is modulus (or remainder).		Unfortunately, this format is more complicated to convert into ROM file offsets, or vice versa, because you have to know more about how the game maps memory. For Zelda II in particular, the formula for converting to a dumped ROM offset is 0x10+(bank*0x4000)+(address%0x4000) -- where % is modulus (or remainder).
−
−	~~=Converting=~~

@@ Line 145: / Line 145: @@
 |8KB (0x2000)
 |}
 =Memory=

@@ Line 184: / Line 184: @@
 More convenient for working with addresses in memory, this representation is used a lot by emulator debugging interfaces in particular. As in [[#Bank And Offset]], an address in this format starts with a bank number, but the second number is its address as mapped into RAM at runtime. So, for example, the above address would be:
-:0x9234
+:0x9234 (bank 5, memory address 0x9234)
-All addresses in banks 0 through 6 will be represented as within the range 0x8000-0xBFFF in this format, while addresses in bank 7 will be in the range 0xC000-0xFFFF:
+For Zelda II, all addresses in banks 0 through 6 will be represented as within the range 0x8000-0xBFFF in this format, while addresses in bank 7 will be in the range 0xC000-0xFFFF:
-:0xD234
+:0xD234 (bank 7, memory address 0xd234)
 Unfortunately, this format is more complicated to convert into ROM file offsets, or vice versa, because you have to know more about how the game maps memory. For Zelda II in particular, the formula for converting to a dumped ROM offset is 0x10+(bank*0x4000)+(address%0x4000) -- where % is modulus (or remainder).
 =Converting=

@@ Line 150: / Line 150: @@
 ==CPU Memory Map==
-==CPU Address==
+This memory map, which is dictated by the way the MMC1 memory mapper maps memory, means that the area of memory between 0x8000 and 0xC000 is switchable. Addresses in this range can refer to any of the 8 PRG banks in the ROM (though in practice, will only ever refer to the first 7). Addresses above 0xC000, however, will *always* map to the last bank ([[PRG Bank 7]]).
 ==Bank And Offset==
 =Converting=

@@ Line 3: / Line 3: @@
 =ROM File=
-NES ROM files are in a format generally called iNES. Most ROMs (including Zelda 2 ROMs) are in [[https://wiki.nesdev.com/w/index.php/INES iNES 1.0 format]]. The layout of a Zelda II ROM file is as follows (an [[https://wiki.nesdev.com/w/index.php/MMC1 MMC1]] cartridge with 8 PRG ROM banks, 16 CHR-ROM banks, and 4KB of SRAM -- for more details see [[https://datacrystal.romhacking.net/wiki/Zelda_II:_The_Adventure_of_Link Data Crystal]]):
+NES ROM files are in a format generally called iNES. Most ROMs (including Zelda 2 ROMs) are in [https://wiki.nesdev.com/w/index.php/INES iNES 1.0 format]. The layout of a Zelda II ROM file is as follows (an [https://wiki.nesdev.com/w/index.php/MMC1 MMC1] cartridge with 8 PRG ROM banks, 16 CHR-ROM banks, and 4KB of SRAM -- for more details see [https://datacrystal.romhacking.net/wiki/Zelda_II:_The_Adventure_of_Link Data Crystal]):
 {| class="wikitable"

@@ Line 5: / Line 5: @@
 NES ROM files are in a format generally called iNES. Most ROMs (including Zelda 2 ROMs) are in [[https://wiki.nesdev.com/w/index.php/INES|iNES 1.0 format]]. The layout of a Zelda II ROM file is as follows (an [[https://wiki.nesdev.com/w/index.php/MMC1|MMC1]] cartridge with 8 PRG ROM banks, 16 CHR-ROM banks, and 4KB of SRAM -- for more details see [[https://datacrystal.romhacking.net/wiki/Zelda_II:_The_Adventure_of_Link|Data Crystal]]):
-{|
+{| class="wikitable"
 !Type
 !Number
 !File Offset
 !Size
 |-
 |iNES Header
@@ Line 20: / Line 21: @@
 |0x00010
 |16KB (0x4000)
 |-
+|
@@ Line 25: / Line 27: @@
 |0x04010
 |16KB (0x4000)
 |-
+|
@@ Line 30: / Line 33: @@
 |0x08010
 |16KB (0x4000)
 |-
+|
@@ Line 35: / Line 39: @@
 |0x0C010
 |16KB (0x4000)
 |-
+|
@@ Line 40: / Line 45: @@
 |0x10010
 |16KB (0x4000)
 |-
+|
@@ Line 45: / Line 51: @@
 |0x14010
 |16KB (0x4000)
 |-
+|
@@ Line 50: / Line 57: @@
 |0x18010
 |16KB (0x4000)
 |-
+|
@@ Line 55: / Line 63: @@
 |0x1C010
 |16KB (0x4000)
 |-
 |CHR Bank
@@ Line 136: / Line 145: @@
 |8KB (0x2000)
 |}
 =Memory=

← Older revision		Revision as of 05:32, 15 April 2021
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	=ROM File Addresses=		=ROM File Addresses=
		+
		+	=Converting=