isa is a pc-only thing, and even then just for very old machines.

Reference: /n/atom/patch/applied2013/isapconly
Date: Sat Sep 21 20:47:53 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/pcpae/io.h	Sat Sep 21 20:47:43 2013
+++ /sys/src/9/pcpae/io.h	Sat Sep 21 20:47:44 2013
@@ -284,8 +284,6 @@
 #define PCIWADDR(va)	(PADDR(va)+PCIWINDOW)
 #define Pciwaddrh(va)	(sizeof(uintmem)>4? (u64int)PCIWADDR(va)>>32: 0)
 #define	Pciwaddrl(va)	PCIWADDR(va)
-#define ISAWINDOW	0
-#define ISAWADDR(va)	(PADDR(va)+ISAWINDOW)
 
 /* SMBus transactions */
 enum
--- /sys/src/9/rb/io.h	Sat Sep 21 20:47:45 2013
+++ /sys/src/9/rb/io.h	Sat Sep 21 20:47:46 2013
@@ -300,8 +300,6 @@
 
 #define PCIWINDOW	0
 #define PCIWADDR(va)	(PADDR(va)+PCIWINDOW)
-#define ISAWINDOW	0
-#define ISAWADDR(va)	(PADDR(va)+ISAWINDOW)
 
 /* SMBus transactions */
 enum
--- /sys/src/9/kw/io.h	Sat Sep 21 20:47:47 2013
+++ /sys/src/9/kw/io.h	Sat Sep 21 20:47:48 2013
@@ -191,8 +191,6 @@
 
 #define PCIWINDOW	0
 #define PCIWADDR(va)	(PADDR(va)+PCIWINDOW)
-#define ISAWINDOW	0
-#define ISAWADDR(va)	(PADDR(va)+ISAWINDOW)
 
 /*
  * Kirkwood stuff