From 40b1d58077256e9ec8715e800019608a1e8cab5f Mon Sep 17 00:00:00 2001
From: Tomas Hruby <tom@minix3.org>
Date: Tue, 29 Sep 2009 20:13:41 +0000
Subject: [PATCH] Mostly a revert of r5306. com.h defines MAX_NR_TASKS value
 which replaces NR_TASKS in the endpoint macros. MAX_NR_TASKS defines the
 maximal number of kernel tasks. It is unlikely that we will ever need this
 many tasks as the goal is not to have such a difference in the future. For
 now it makes possible to remove the limiting NR_TASKS from the endpoint code.

---
 include/minix/com.h      |  7 +++----
 include/minix/endpoint.h | 13 ++++++-------
 test/test39.c            |  5 +++--
 3 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/include/minix/com.h b/include/minix/com.h
index 33c860980..b4d24d8f2 100755
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -9,10 +9,8 @@
 #define ANY		0x7ace	/* used to indicate 'any process' */
 #define NONE 		0x6ace  /* used to indicate 'no process at all' */
 #define SELF		0x8ace 	/* used to indicate 'own process' */
-/* check if the magic process numbers are valid process table slot numbers */
-#if (ANY < NR_PROCS)
-#error "Magic process number in the process table range"
-#endif
+#define _MAX_MAGIC_PROC (SELF)	/* used by <minix/endpoint.h> 
+				   to determine generation size */
 
 /*===========================================================================*
  *            	Process numbers of processes in the system image	     *
@@ -33,6 +31,7 @@
 #define HARDWARE     KERNEL	/* for hardware interrupt handlers */
 
 /* Number of tasks. Note that NR_PROCS is defined in <minix/config.h>. */
+#define MAX_NR_TASKS	1023
 #define NR_TASKS	  4 
 
 /* User-space processes, that is, device drivers, servers, and INIT. */
diff --git a/include/minix/endpoint.h b/include/minix/endpoint.h
index a646d1657..54dc7b9d6 100644
--- a/include/minix/endpoint.h
+++ b/include/minix/endpoint.h
@@ -16,14 +16,13 @@
  * the generation size is big enough to start the next generation
  * above the highest magic number.
  */
-#define _ENDPOINT_GENERATION_BITS	16
-#define _ENDPOINT_PNUM_BITS		16
-#define _ENDPOINT_MAX_GENERATION	((1 << _ENDPOINT_GENERATION_BITS)-1)
-#define _ENDPOINT_MAX_PNUM		((1 << _ENDPOINT_PNUM_BITS) - 1)
+#define _ENDPOINT_GENERATION_SIZE (MAX_NR_TASKS+_MAX_MAGIC_PROC+1)
+#define _ENDPOINT_MAX_GENERATION  (INT_MAX/_ENDPOINT_GENERATION_SIZE-1)
 
 /* Generation + Process slot number <-> endpoint. */
-#define _ENDPOINT(g, p)	((endpoint_t)(((g) << _ENDPOINT_PNUM_BITS) | (p)))
-#define _ENDPOINT_G(e) 	((u16_t)((e) >> _ENDPOINT_PNUM_BITS))
-#define _ENDPOINT_P(e) 	((i16_t)((e) & _ENDPOINT_MAX_PNUM))
+#define _ENDPOINT(g, p) ((endpoint_t)((g) * _ENDPOINT_GENERATION_SIZE + (p)))
+#define _ENDPOINT_G(e) (((e)+MAX_NR_TASKS) / _ENDPOINT_GENERATION_SIZE)
+#define _ENDPOINT_P(e) \
+	((((e)+MAX_NR_TASKS) % _ENDPOINT_GENERATION_SIZE) - MAX_NR_TASKS)
 
 #endif
diff --git a/test/test39.c b/test/test39.c
index cd99ff7cb..928776153 100644
--- a/test/test39.c
+++ b/test/test39.c
@@ -10,8 +10,9 @@ int main(int argc, char *argv[])
 	printf("Test 39 ");
 
 	for(g = 0; g <= _ENDPOINT_MAX_GENERATION; g++) {
-		for(p = -NR_TASKS; p < _NR_PROCS; p++) {
-			int e, mg, mp;
+		for(p = -MAX_NR_TASKS; p < _NR_PROCS; p++) {
+			endpoint_t e;
+			int mg, mp;
 			e = _ENDPOINT(g, p);
 			mg = _ENDPOINT_G(e);
 			mp = _ENDPOINT_P(e);