diff --git a/exec.c b/exec.c
index 0c7096b..cf8632c 100644
--- a/exec.c
+++ b/exec.c
@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.102 2012/10/21 21:26:39 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.103 2012/10/21 21:39:01 tg Exp $");
 
 #ifndef MKSH_DEFAULT_EXECSHELL
 #define MKSH_DEFAULT_EXECSHELL	"/bin/sh"
@@ -464,7 +464,7 @@ execute(struct op * volatile t,
 			errorf("%s: %s", s, strerror(rv));
 	}
  Break:
-	exstat = rv;
+	exstat = rv & 0xFF;
 	if (vp_pipest->flag & INT_L) {
 		unset(vp_pipest, 1);
 		vp_pipest->flag = DEFINED | ISSET | INTEGER | RDONLY |
@@ -741,7 +741,7 @@ comexec(struct op *t, struct tbl * volatile tp, const char **ap,
 		e->type = E_FUNC;
 		if (!(i = kshsetjmp(e->jbuf))) {
 			/* seems odd to pass XERROK here, but AT&T ksh does */
-			exstat = execute(tp->val.t, flags & XERROK, xerrok);
+			exstat = execute(tp->val.t, flags & XERROK, xerrok) & 0xFF;
 			i = LRETURN;
 		}
 		kshname = old_kshname;
@@ -762,7 +762,7 @@ comexec(struct op *t, struct tbl * volatile tp, const char **ap,
 		switch (i) {
 		case LRETURN:
 		case LERROR:
-			rv = exstat;
+			rv = exstat & 0xFF;
 			break;
 		case LINTR:
 		case LEXIT:
@@ -822,7 +822,7 @@ comexec(struct op *t, struct tbl * volatile tp, const char **ap,
 	}
  Leave:
 	if (flags & XEXEC) {
-		exstat = rv;
+		exstat = rv & 0xFF;
 		unwind(LLEAVE);
 	}
 	return (rv);
diff --git a/funcs.c b/funcs.c
index f59abdc..d7b179c 100644
--- a/funcs.c
+++ b/funcs.c
@@ -38,7 +38,7 @@
 #endif
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.226 2012/10/03 17:24:19 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.227 2012/10/21 21:39:02 tg Exp $");
 
 #if HAVE_KILLPG
 /*
@@ -2280,7 +2280,7 @@ c_exitreturn(const char **wp)
 			exstat = 1;
 			warningf(true, "%s: %s", arg, "bad number");
 		} else
-			exstat = n;
+			exstat = n & 0xFF;
 	} else if (trap_exstat != -1)
 		exstat = trap_exstat;
 	if (wp[0][0] == 'r') {
diff --git a/histrap.c b/histrap.c
index fd8a4b4..a87440d 100644
--- a/histrap.c
+++ b/histrap.c
@@ -27,7 +27,7 @@
 #include <sys/file.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.126 2012/06/24 19:47:11 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.127 2012/10/21 21:39:03 tg Exp $");
 
 Trap sigtraps[NSIG + 1];
 static struct sigaction Sigact_ign;
@@ -1224,12 +1224,12 @@ runtrap(Trap *p, bool is_last)
 		/* SIG_DFL */
 		if (p->flags & TF_FATAL) {
 			/* eg, SIGHUP */
-			exstat = 128 + i;
+			exstat = (int)ksh_min(128U + (unsigned)i, 255U);
 			unwind(LLEAVE);
 		}
 		if (p->flags & TF_DFL_INTR) {
 			/* eg, SIGINT, SIGQUIT, SIGTERM, etc. */
-			exstat = 128 + i;
+			exstat = (int)ksh_min(128U + (unsigned)i, 255U);
 			unwind(LINTR);
 		}
 		goto donetrap;
@@ -1244,7 +1244,7 @@ runtrap(Trap *p, bool is_last)
 		p->trap = NULL;
 	}
 	if (trap_exstat == -1)
-		trap_exstat = exstat;
+		trap_exstat = exstat & 0xFF;
 	/*
 	 * Note: trapstr is fully parsed before anything is executed, thus
 	 * no problem with afree(p->trap) in settrap() while still in use.
diff --git a/main.c b/main.c
index da6ffaf..1fe19eb 100644
--- a/main.c
+++ b/main.c
@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.230 2012/10/21 21:26:40 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.231 2012/10/21 21:39:04 tg Exp $");
 
 extern char **environ;
 
@@ -711,7 +711,7 @@ include(const char *name, int argc, const char **argv, int intr_ok)
 			 * intr_ok is set if we are including .profile or $ENV.
 			 * If user ^Cs out, we don't want to kill the shell...
 			 */
-			if (intr_ok && (exstat - 128) != SIGTERM)
+			if (intr_ok && ((exstat & 0xFF) - 128) != SIGTERM)
 				return (1);
 			/* FALLTHROUGH */
 		case LEXIT:
@@ -855,7 +855,7 @@ shell(Source * volatile s, volatile bool toplevel)
 			t->u.evalflags |= DOTCOMEXEC;
 #endif
 		if (!Flag(FNOEXEC) || (s->flags & SF_TTY))
-			exstat = execute(t, 0, NULL);
+			exstat = execute(t, 0, NULL) & 0xFF;
 
 		if (t->type != TEOF && interactive && really_exit)
 			really_exit = false;
@@ -865,7 +865,7 @@ shell(Source * volatile s, volatile bool toplevel)
 	}
 	quitenv(NULL);
 	source = old_source;
-	return (exstat);
+	return (exstat & 0xFF);
 }
 
 /* return to closest error handler or shell(), exit if none found */
@@ -961,7 +961,7 @@ quitenv(struct shf *shf)
 #endif
 			j_exit();
 			if (ep->flags & EF_FAKE_SIGDIE) {
-				int sig = exstat - 128;
+				int sig = (exstat & 0xFF) - 128;
 
 				/*
 				 * ham up our death a bit (AT&T ksh
@@ -980,7 +980,7 @@ quitenv(struct shf *shf)
 		if (shf)
 			shf_close(shf);
 		reclaim();
-		exit(exstat);
+		exit(exstat & 0xFF);
 	}
 	if (shf)
 		shf_close(shf);
diff --git a/sh.h b/sh.h
index 2350a38..3a908dc 100644
--- a/sh.h
+++ b/sh.h
@@ -157,7 +157,7 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.593 2012/10/21 21:26:41 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.594 2012/10/21 21:39:05 tg Exp $");
 #endif
 #define MKSH_VERSION "R40 2012/10/03"
 
@@ -293,6 +293,8 @@ struct rusage {
 #define ksh_toupper(c)	(((c) >= 'a') && ((c) <= 'z') ? (c) - 'a' + 'A' : (c))
 #define ksh_isdash(s)	(((s) != NULL) && ((s)[0] == '-') && ((s)[1] == '\0'))
 #define ksh_isspace(c)	((((c) >= 0x09) && ((c) <= 0x0D)) || ((c) == 0x20))
+#define ksh_min(x,y)	((x) < (y) ? (x) : (y))
+#define ksh_max(x,y)	((x) > (y) ? (x) : (y))
 
 #ifdef MKSH__NO_PATH_MAX
 #undef PATH_MAX
diff --git a/var.c b/var.c
index c06d213..9fefc42 100644
--- a/var.c
+++ b/var.c
@@ -27,7 +27,7 @@
 #include <sys/sysctl.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/var.c,v 1.153 2012/07/30 21:37:17 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/var.c,v 1.154 2012/10/21 21:39:06 tg Exp $");
 
 /*-
  * Variables
@@ -260,7 +260,7 @@ global(const char *n)
 				vp->flag &= ~(ISSET|INTEGER);
 			break;
 		case '?':
-			vp->val.i = exstat;
+			vp->val.i = exstat & 0xFF;
 			break;
 		case '#':
 			vp->val.i = l->argc;