Add parts/platforms

parts/platforms/README.md

@@ -0,0 +1,5 @@
+# platforms
+
+This is a collection of include files that set platform-specific constants
+that different parts use. When assembling your own OS, pick the platform include
+that is closest to yours and adapt it to your machine.

parts/platforms/rc2014.inc

@@ -0,0 +1,5 @@
+; classic RC2014 setup (8K ROM + 32K RAM) and a stock Serial I/O module
+
+RAMEND		.equ	0xa000
+ACIA_CTL	.equ	0x80	; Control and status. RS off.
+ACIA_IO		.equ	0x81	; Transmit. RS on.

parts/shell/shell.asm

@@ -5,13 +5,7 @@
 ; *** STATUS ***
 ; Incomplete. This just outputs the welcome prompt then halts
 
-; *** PLATFORM ***
-; this is specific to a classic RC2014 setup (8K ROM + 32K RAM). This will be
-; reorganized into something better.
-
-RAMEND		.equ	0xa000
-ACIA_CTL	.equ	0x80	; Control and status. RS off.
-ACIA_IO		.equ	0x81	; Transmit. RS on.
+#include "platform.inc"
 
 ; *** CONSTS ***
 CR	.equ	0x0d

recipes/rc2014.md

@@ -31,7 +31,8 @@ device I use in this recipe.
 
 ### Gathering parts
 
-* `shell.asm` from `parts`
+* `parts/platforms/rc2014.inc` as `platform.inc`
+* `parts/shell/shell.asm` as `shell.asm`
 * [scas][scas]
 * [romwrite][romwrite] and its specified dependencies
 * [GNU screen][screen]