ASCII-EX mapper - Revision history

Aoineko at 23:07, 11 December 2023

2023-12-11T23:07:48Z

2023-11-24T10:31:08Z

‎Annexe

2023-11-24T10:30:19Z

‎Principles

2023-11-24T10:28:06Z

‎ASCII-EX16 mapper

2023-11-24T10:26:04Z

‎Misc

2023-11-23T22:50:57Z

‎Principales

2023-11-23T22:50:28Z

2023-11-23T22:49:41Z

2023-11-23T22:48:53Z

‎Principales

2023-11-23T22:48:22Z

‎MSXgl

← Older revision		Revision as of 23:07, 11 December 2023
Line 104:		Line 104:
	SET_BANK_SEGMENT(1, 30);		SET_BANK_SEGMENT(1, 30);

−	[[Category:Proposal]]	+	[[Category:Proposal]][[Category:Proposal/Mapper]]

@@ Line 66: / Line 66: @@
 * Maximum ROM size: 32 MB
-== Annexe ==
+== Appendix ==
 === Bank switching cost ===

@@ Line 10: / Line 10: @@
 For the time being, we propose to reserve the 4 most significant bits for future extensions for the format (such as SRAM or sound chips support for example).
 This leaves 12 bits to select which segment is visible in each bank, for a maximum of 4096 segments.
 {| class="wikitable"
@@ Line 27: / Line 28: @@
 |}
 The maximum ROM size is therefore 32 MB (for 8 KB segments) or 64 MB (for 16 KB segments).

@@ Line 47: / Line 47: @@
 * Maximum number of segments: 4096
-* Maximum ROM size: 64 MB (1024 MB)
+* Maximum ROM size: 64 MB
 === ASCII-EX8 mapper ===

@@ Line 66: / Line 66: @@
 * Maximum ROM size: 32 MB
-== Misc ==
+== Annexe ==
 === Bank switching cost ===

@@ Line 1: / Line 1: @@
 Here's a proposal for a mapper format operating with a 16-bit segment register and allowing ROMs larger than the 2/4 MB limit of classic mappers.
-== Principales ==
+== Principles ==
 The idea is to extend the ASCII mapper format using a 16-bit segment register so we could build hardware capable of running standard ASCII8/16 ROMs in addition to the new 16-bit format.

@@ Line 66: / Line 66: @@
 * Maximum ROM size: 32 MB
-== Bank switching cost ==
+== Misc ==
 The cost of switching only the lower or higher byte of the 16-bit segment register is the same that switching segment for standard ASCII mappers.
@@ Line 89: / Line 91: @@
   INC HL      ;  7 t-states
   LD (HL),D   ;  8 t-states
 === Naming ===

@@ Line 31: / Line 31: @@
 Detection by emulators should be fairly easy (counting ROM write accesses).
 Below, the parts in blue are the only additions to the standard ASCII8/16 format.
-== ASCII-EX16 mapper ==
+=== ASCII-EX16 mapper ===
 {| class="wikitable"
@@ Line 47: / Line 49: @@
 * Maximum ROM size: 64 MB (1024 MB)
-== ASCII-EX8 mapper ==
+=== ASCII-EX8 mapper ===
 {| class="wikitable"

← Older revision		Revision as of 22:48, 23 November 2023
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	\|}		\|}

		+	The reserved bits, must be set to 0.
	The maximum ROM size is therefore 32 MB (for 8 KB segments) or 64 MB (for 16 KB segments).		The maximum ROM size is therefore 32 MB (for 8 KB segments) or 64 MB (for 16 KB segments).

@@ Line 94: / Line 94: @@
 === MSXgl ===
-MSXgl uses macros to encapsulate bank switching mechanisms. It would therefore be totally transparent for a user to switch from an ASCII8 or even Konami-SCC mapper, to an ASCII-EX8 mapper.
+MSXgl uses macros to encapsulate bank switching mechanisms. It would therefore be totally transparent for a user to switch, for example, from an ASCII8 or even Konami-SCC mapper, to an ASCII-EX8 mapper.
   #define SET_BANK_SEGMENT(bank, segment) /* ... */
-  // Make segment #300 visible through bank #1
+  // Make segment #30 visible through bank #1
-  SET_BANK_SEGMENT(1, 300);
+  SET_BANK_SEGMENT(1, 30);
 [[Category:Proposal]]