--- gforth/engine/threaded.h	1999/05/04 12:51:35	1.4
+++ gforth/engine/threaded.h	2007/02/26 19:07:05	1.36
@@ -1,6 +1,6 @@
 /* This file defines a number of threading schemes.
 
-  Copyright (C) 1995, 1996,1997 Free Software Foundation, Inc.
+  Copyright (C) 1995, 1996,1997,1999,2003,2004,2005 Free Software Foundation, Inc.
 
   This file is part of Gforth.
 
@@ -16,7 +16,7 @@
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
-  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 
 
   This files defines macros for threading. Many sets of macros are
@@ -91,304 +91,132 @@
 
 */
 
-/* CFA_NEXT: a more appropriate name would be CFA_LIVE, i.e., cfa is live after NEXT */
+#if !defined(GCC_PR15242_WORKAROUND)
+#if __GNUC__ == 3
+/* various gcc-3.x version have problems (including PR15242) that are
+   solved with this workaround */
+#define GCC_PR15242_WORKAROUND 1
+#else
+/* other gcc versions are better off without the workaround for
+   primitives that are not relocatable */
+#define GCC_PR15242_WORKAROUND 0
+#endif
+#endif
 
-#ifdef DOUBLY_INDIRECT
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip;})
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ip++; ca=**cfa;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({DEF_CA cfa=(XT); ca=**cfa; goto *ca;})
-#  define NEXT1_P1 ({ca = **cfa;})
-#  define NEXT1_P2 ({goto *ca;})
+#if GCC_PR15242_WORKAROUND
+#define DO_GOTO goto before_goto
+#else
+#define DO_GOTO goto *real_ca
+#endif
 
-#else /* !defined(DOUBLY_INDIRECT) */
+#ifndef GOTO_ALIGN
+#define GOTO_ALIGN
+#endif
 
-#if defined(DIRECT_THREADED)
+#define GOTO(target) do {(real_ca=(target));} while(0)
+#define NEXT_P2 do {NEXT_P1_5; DO_GOTO;} while(0)
+#define EXEC(XT) do { real_ca=EXEC1(XT); DO_GOTO;} while (0)
+#define VM_JUMP(target) do {GOTO(target);} while (0)
+#define NEXT do {DEF_CA NEXT_P1; NEXT_P2;} while(0)
+#define FIRST_NEXT_P2 NEXT_P1_5; GOTO_ALIGN; \
+before_goto: goto *real_ca; after_goto:
+#define FIRST_NEXT do {DEF_CA NEXT_P1; FIRST_NEXT_P2;} while(0)
+#define IPTOS NEXT_INST
 
-/* note that the "cfa dead" versions only work if GETCFA exists and works */
 
-#if THREADING_SCHEME==1
-#warning direct threading scheme 1: autoinc, long latency, cfa live
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip++;})
-#  define IP		(ip-1)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({goto *cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#endif
+#ifdef DOUBLY_INDIRECT
+# ifndef DEBUG_DITC
+#  define DEBUG_DITC 0
+# endif
+/* define to 1 if you want to check consistency */
+#  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
+#  define CFA		cfa1
+#  define MORE_VARS     Xt cfa1;
+#  define IP		(ip)
+#  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
+#  define NEXT_INST	(cfa)
+#  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
+#  define DEF_CA	Label ca;
+#  define NEXT_P1	do {\
+  if (DEBUG_DITC && (cfa<=vm_prims+DOESJUMP || cfa>=vm_prims+npriminfos)) \
+    fprintf(stderr,"NEXT encountered prim %p at ip=%p\n", cfa, ip); \
+  ip++;} while(0)
+#  define NEXT_P1_5	do {ca=**cfa; GOTO(ca);} while(0)
+#  define EXEC1(XT)	({DEF_CA cfa=(XT);\
+  if (DEBUG_DITC && (cfa>vm_prims+DOESJUMP && cfa<vm_prims+npriminfos)) \
+    fprintf(stderr,"EXEC encountered xt %p at ip=%p, vm_prims=%p, xts=%p\n", cfa, ip, vm_prims, xts); \
+ ca=**cfa; ca;})
+
+#elif defined(NO_IP)
+
+#define NEXT_P0
+#  define CFA		cfa
+#define SET_IP(target)	assert(0)
+#define INC_IP(n)	((void)0)
+#define DEF_CA
+#define NEXT_P1
+#define NEXT_P1_5		do {goto *next_code;} while(0)
+/* set next_code to the return address before performing EXEC */
+/* original: */
+/* #define EXEC1(XT)	do {cfa=(XT); goto **cfa;} while(0) */
+/* fake, to make syntax check work */
+#define EXEC1(XT)	({cfa=(XT); *cfa;})
 
-#if THREADING_SCHEME==2
-#warning direct threading scheme 2: autoinc, long latency, cfa dead
-#ifndef GETCFA
-#error GETCFA must be defined for cfa dead threading
-#endif
-#  define NEXT_P0	(ip++)
-#  define IP		(ip-1)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*(ip-1))
-#  define INC_IP(const_inc)	({ ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({goto **(ip-1);})
-#  define EXEC(XT)	({goto *(XT);})
-#endif
+#else  /* !defined(DOUBLY_INDIRECT) && !defined(NO_IP) */
 
+#if defined(DIRECT_THREADED)
 
-#if THREADING_SCHEME==3
-#warning direct threading scheme 3: autoinc, low latency, cfa live
-#  define CFA_NEXT
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1	({cfa=*ip++;})
-#  define NEXT_P2	({goto *cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#endif
+/* This lets the compiler know that cfa is dead before; we place it at
+   "goto *"s that perform direct threaded dispatch (i.e., not EXECUTE
+   etc.), and thus do not reach doers, which would use cfa; the only
+   way to a doer is through EXECUTE etc., which set the cfa
+   themselves.
 
-#if THREADING_SCHEME==4
-#warning direct threading scheme 4: autoinc, low latency, cfa dead
-#ifndef GETCFA
-#error GETCFA must be defined for cfa dead threading
-#endif
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({goto **(ip++);})
-#  define EXEC(XT)	({goto *(XT);})
-#endif
+   Some of these direct threaded schemes use "cfa" to hold the code
+   address in normal direct threaded code.  Of course we cannot use
+   KILLS there.
 
-#if THREADING_SCHEME==5
-#warning direct threading scheme 5: long latency, cfa live
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip;})
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1	(ip++)
-#  define NEXT_P2	({goto *cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#endif
+   KILLS works by having an empty asm instruction, and claiming to the
+   compiler that it writes to cfa.
 
-#if THREADING_SCHEME==6
-#warning direct threading scheme 6: long latency, cfa dead
-#ifndef GETCFA
-#error GETCFA must be defined for cfa dead threading
-#endif
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1	(ip++)
-#  define NEXT_P2	({goto **(ip-1);})
-#  define EXEC(XT)	({goto *(XT);})
-#endif
+   KILLS is optional.  You can write
 
+#define KILLS
 
-#if THREADING_SCHEME==7
-#warning direct threading scheme 7: low latency, cfa live
-#  define CFA_NEXT
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1	({cfa=*ip++;})
-#  define NEXT_P2	({goto *cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#endif
+   and lose just a little performance.
+*/
+#define KILLS asm("":"=X"(cfa));
 
-#if THREADING_SCHEME==8
 #warning direct threading scheme 8: cfa dead, i386 hack
-#ifndef GETCFA
-#error GETCFA must be defined for cfa dead threading
-#endif
 #  define NEXT_P0
+#  define CFA		cfa
 #  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
+#  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
 #  define NEXT_INST	(*IP)
-#  define INC_IP(const_inc)	({ ip+=(const_inc);})
+#  define INC_IP(const_inc)	do { ip+=(const_inc);} while(0)
 #  define DEF_CA
 #  define NEXT_P1	(ip++)
-#  define NEXT_P2	({goto **(ip-1);})
-#  define EXEC(XT)	({goto *(XT);})
-#endif
-
-#if THREADING_SCHEME==9
-#warning direct threading scheme 9: Power/PPC hack, long latency
-/* Power uses a prepare-to-branch instruction, and the latency between
-   this inst and the branch is 5 cycles on a PPC604; so we utilize this
-   to do some prefetching in between */
-#  define CFA_NEXT
-#  define NEXT_P0
-#  define IP		ip
-#  define SET_IP(p)	({ip=(p); next_cfa=*ip; NEXT_P0;})
-#  define NEXT_INST	(next_cfa)
-#  define INC_IP(const_inc)	({next_cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ca=next_cfa; cfa=next_cfa; ip++; next_cfa=*ip;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#  define MORE_VARS	Xt next_cfa;
-#endif
-
-#if THREADING_SCHEME==10
-#warning direct threading scheme 10: plain (no attempt at scheduling)
-#  define CFA_NEXT
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({cfa=*ip++; goto *cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto *cfa;})
-#endif
+#  define NEXT_P1_5	do {KILLS GOTO(*(ip-1));} while(0)
+#  define EXEC1(XT)	({cfa=(XT); *cfa;})
 
 /* direct threaded */
 #else
 /* indirect THREADED  */
 
-#if THREADING_SCHEME==1
-#warning indirect threading scheme 1: autoinc, long latency, cisc
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip++;})
-#  define IP		(ip-1)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({goto **cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto **cfa;})
-#endif
-
-#if THREADING_SCHEME==2
-#warning indirect threading scheme 2: autoinc, long latency
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip++;})
-#  define IP		(ip-1)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ca=*cfa;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({DEF_CA cfa=(XT); ca=*cfa; goto *ca;})
-#endif
-
-
-#if THREADING_SCHEME==3
-#warning indirect threading scheme 3: autoinc, low latency, cisc
-#  define CFA_NEXT
-#  define NEXT_P0
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1
-#  define NEXT_P2	({cfa=*ip++; goto **cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto **cfa;})
-#endif
-
-#if THREADING_SCHEME==4
-#warning indirect threading scheme 4: autoinc, low latency
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip++;})
-#  define IP		(ip-1)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ca=*cfa;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({DEF_CA cfa=(XT); ca=*cfa; goto *ca;})
-#endif
-
-
-#if THREADING_SCHEME==5
-#warning indirect threading scheme 5: long latency, cisc
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip;})
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA
-#  define NEXT_P1	(ip++)
-#  define NEXT_P2	({goto **cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto **cfa;})
-#endif
-
-#if THREADING_SCHEME==6
-#warning indirect threading scheme 6: long latency
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip;})
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ip++; ca=*cfa;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({DEF_CA cfa=(XT); ca=*cfa; goto *ca;})
-#endif
-
-#if THREADING_SCHEME==7
-#warning indirect threading scheme 7: low latency
-#  define CFA_NEXT
-#  define NEXT_P0	({cfa=*ip;})
-#  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
-#  define NEXT_INST	(cfa)
-#  define INC_IP(const_inc)	({cfa=IP[const_inc]; ip+=(const_inc);})
-#  define DEF_CA	Label ca;
-#  define NEXT_P1	({ip++; ca=*cfa;})
-#  define NEXT_P2	({goto *ca;})
-#  define EXEC(XT)	({DEF_CA cfa=(XT); ca=*cfa; goto *ca;})
-#endif
-
-#if THREADING_SCHEME==8
 #warning indirect threading scheme 8: low latency,cisc
-#  define CFA_NEXT
 #  define NEXT_P0
+#  define CFA		cfa
 #  define IP		(ip)
-#  define SET_IP(p)	({ip=(p); NEXT_P0;})
+#  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
 #  define NEXT_INST	(*ip)
-#  define INC_IP(const_inc)	({ip+=(const_inc);})
+#  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
 #  define DEF_CA
 #  define NEXT_P1
-#  define NEXT_P2	({cfa=*ip++; goto **cfa;})
-#  define EXEC(XT)	({cfa=(XT); goto **cfa;})
-#endif
+#  define NEXT_P1_5	do {cfa=*ip++; GOTO(*cfa);} while(0)
+#  define EXEC1(XT)	({cfa=(XT); *cfa;})
 
 /* indirect threaded */
 #endif
 
-#endif /* !defined(DOUBLY_INDIRECT) */
-
-#define NEXT ({DEF_CA NEXT_P1; NEXT_P2;})
+#endif /* !defined(DOUBLY_INDIRECT) && !defined(NO_IP) */