File:  [gforth] / gforth / engine / threaded.h
Revision 1.30: download - view: text, annotated - select for diffs
Sun Jan 23 13:56:13 2005 UTC (15 years ago) by pazsan
Branches: MAIN
CVS tags: HEAD
Fixed problems with workaround

    1: /* This file defines a number of threading schemes.
    2: 
    3:   Copyright (C) 1995, 1996,1997,1999,2003,2004 Free Software Foundation, Inc.
    4: 
    5:   This file is part of Gforth.
    6: 
    7:   Gforth is free software; you can redistribute it and/or
    8:   modify it under the terms of the GNU General Public License
    9:   as published by the Free Software Foundation; either version 2
   10:   of the License, or (at your option) any later version.
   11: 
   12:   This program is distributed in the hope that it will be useful,
   13:   but WITHOUT ANY WARRANTY; without even the implied warranty of
   14:   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15:   GNU General Public License for more details.
   16: 
   17:   You should have received a copy of the GNU General Public License
   18:   along with this program; if not, write to the Free Software
   19:   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
   20: 
   21: 
   22:   This files defines macros for threading. Many sets of macros are
   23:   defined. Functionally they have only one difference: Some implement
   24:   direct threading, some indirect threading. The other differences are
   25:   just variations to help GCC generate faster code for various
   26:   machines.
   27: 
   28:   (Well, to tell the truth, there actually is another functional
   29:   difference in some pathological cases: e.g., a '!' stores into the
   30:   cell where the next executed word comes from; or, the next word
   31:   executed comes from the top-of-stack. These differences are one of
   32:   the reasons why GCC cannot produce the right variation by itself. We
   33:   chose disallowing such practices and using the added implementation
   34:   freedom to achieve a significant speedup, because these practices
   35:   are not common in Forth (I have never heard of or seen anyone using
   36:   them), and it is easy to circumvent problems: A control flow change
   37:   will flush any prefetched words; you may want to do a "0
   38:   drop" before that to write back the top-of-stack cache.)
   39: 
   40:   These macro sets are used in the following ways: After translation
   41:   to C a typical primitive looks like
   42: 
   43:   ...
   44:   {
   45:   DEF_CA
   46:   other declarations
   47:   NEXT_P0;
   48:   main part of the primitive
   49:   NEXT_P1;
   50:   store results to stack
   51:   NEXT_P2;
   52:   }
   53: 
   54:   DEF_CA and all the NEXT_P* together must implement NEXT; In the main
   55:   part the instruction pointer can be read with IP, changed with
   56:   INC_IP(const_inc), and the cell right behind the presently executing
   57:   word (i.e. the value of *IP) is accessed with NEXT_INST.
   58: 
   59:   If a primitive does not fall through the main part, it has to do the
   60:   rest by itself. If it changes ip, it has to redo NEXT_P0 (perhaps we
   61:   should define a macro SET_IP).
   62: 
   63:   Some primitives (execute, dodefer) do not end with NEXT, but with
   64:   EXEC(.). If NEXT_P0 has been called earlier, it has to perform
   65:   "ip=IP;" to ensure that ip has the right value (NEXT_P0 may change
   66:   it).
   67: 
   68:   Finally, there is NEXT1_P1 and NEXT1_P2, which are parts of EXEC
   69:   (EXEC(XT) could be defined as "cfa=XT; NEXT1_P1; NEXT1_P2;" (is this
   70:   true?)) and are used for making docol faster.
   71: 
   72:   We can define the ways in which these macros are used with a regular
   73:   expression:
   74: 
   75:   For a primitive
   76: 
   77:   DEF_CA NEXT_P0 ( IP | INC_IP | NEXT_INST | ip=...; NEXT_P0 ) * ( NEXT_P1 NEXT_P2 | EXEC(...) )
   78: 
   79:   For a run-time routine, e.g., docol:
   80:   PFA1(cfa) ( NEXT_P0 NEXT | cfa=...; NEXT1_P1; NEXT1_P2 | EXEC(...) )
   81: 
   82:   This comment does not yet describe all the dependences that the
   83:   macros have to satisfy.
   84: 
   85:   To organize the former ifdef chaos, each path is separated
   86:   This gives a quite impressive number of paths, but you clearly
   87:   find things that go together.
   88: 
   89:   It should be possible to organize the whole thing in a way that
   90:   contains less redundancy and allows a simpler description.
   91: 
   92: */
   93: 
   94: #ifdef GCC_PR15242_WORKAROUND
   95: #define DO_GOTO goto before_goto
   96: #else
   97: #define DO_GOTO goto *real_ca
   98: #endif
   99: #ifndef GOTO_ALIGN
  100: #define GOTO_ALIGN
  101: #endif
  102: 
  103: #define GOTO(target) do {(real_ca=(target));} while(0)
  104: #define NEXT_P2 do {NEXT_P1_5; DO_GOTO;} while(0)
  105: #define EXEC(XT) do { EXEC1(XT); DO_GOTO;} while (0)
  106: #define NEXT do {DEF_CA NEXT_P1; NEXT_P2;} while(0)
  107: #define FIRST_NEXT_P2 NEXT_P1_5; GOTO_ALIGN; \
  108: before_goto: goto *real_ca; after_goto:
  109: #define FIRST_NEXT DEF_CA NEXT_P1; FIRST_NEXT_P2;
  110: #define IPTOS NEXT_INST
  111: 
  112: 
  113: #ifdef DOUBLY_INDIRECT
  114: # ifndef DEBUG_DITC
  115: #  define DEBUG_DITC 0
  116: # endif
  117: /* define to 1 if you want to check consistency */
  118: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
  119: #  define CFA		cfa1
  120: #  define MORE_VARS     Xt cfa1;
  121: #  define IP		(ip)
  122: #  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
  123: #  define NEXT_INST	(cfa)
  124: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  125: #  define DEF_CA	Label ca;
  126: #  define NEXT_P1	do {\
  127:   if (DEBUG_DITC && (cfa<=vm_prims+DOESJUMP || cfa>=vm_prims+npriminfos)) \
  128:     fprintf(stderr,"NEXT encountered prim %p at ip=%p\n", cfa, ip); \
  129:   ip++;} while(0)
  130: #  define NEXT_P1_5	do {ca=**cfa; GOTO(ca);} while(0)
  131: #  define EXEC1(XT)	do {DEF_CA cfa=(XT);\
  132:   if (DEBUG_DITC && (cfa>vm_prims+DOESJUMP && cfa<vm_prims+npriminfos)) \
  133:     fprintf(stderr,"EXEC encountered xt %p at ip=%p, vm_prims=%p, xts=%p\n", cfa, ip, vm_prims, xts); \
  134:  ca=**cfa; GOTO(ca);} while(0)
  135: 
  136: #elif defined(NO_IP)
  137: 
  138: #define NEXT_P0
  139: #  define CFA		cfa
  140: #define SET_IP(target)	assert(0)
  141: #define INC_IP(n)	((void)0)
  142: #define DEF_CA
  143: #define NEXT_P1
  144: #define NEXT_P1_5		do {goto *next_code;} while(0)
  145: /* set next_code to the return address before performing EXEC */
  146: #define EXEC1(XT)	do {cfa=(XT); goto **cfa;} while(0)
  147: 
  148: #else  /* !defined(DOUBLY_INDIRECT) && !defined(NO_IP) */
  149: 
  150: #if defined(DIRECT_THREADED)
  151: 
  152: /* This lets the compiler know that cfa is dead before; we place it at
  153:    "goto *"s that perform direct threaded dispatch (i.e., not EXECUTE
  154:    etc.), and thus do not reach doers, which would use cfa; the only
  155:    way to a doer is through EXECUTE etc., which set the cfa
  156:    themselves.
  157: 
  158:    Some of these direct threaded schemes use "cfa" to hold the code
  159:    address in normal direct threaded code.  Of course we cannot use
  160:    KILLS there.
  161: 
  162:    KILLS works by having an empty asm instruction, and claiming to the
  163:    compiler that it writes to cfa.
  164: 
  165:    KILLS is optional.  You can write
  166: 
  167: #define KILLS
  168: 
  169:    and lose just a little performance.
  170: */
  171: #define KILLS asm("":"=X"(cfa));
  172: 
  173: #ifndef THREADING_SCHEME
  174: #define THREADING_SCHEME 7
  175: #endif
  176: 
  177: #if THREADING_SCHEME==1
  178: #warning direct threading scheme 1: autoinc, long latency, cfa live
  179: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip++;} while(0)
  180: #  define CFA		cfa1
  181: #  define MORE_VARS     Xt cfa1;
  182: #  define IP		(ip-1)
  183: #  define SET_IP(p)	do {ip=(p); cfa=*ip++;} while(0)
  184: #  define NEXT_INST	(cfa)
  185: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  186: #  define DEF_CA
  187: #  define NEXT_P1
  188: #  define NEXT_P1_5	do {GOTO(cfa);} while(0)
  189: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  190: #endif
  191: 
  192: #if THREADING_SCHEME==2
  193: #warning direct threading scheme 2: autoinc, long latency, cfa dead
  194: #  define NEXT_P0	(ip++)
  195: #  define CFA		cfa
  196: #  define IP		(ip-1)
  197: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  198: #  define NEXT_INST	(*(ip-1))
  199: #  define INC_IP(const_inc)	do { ip+=(const_inc);} while(0)
  200: #  define DEF_CA
  201: #  define NEXT_P1
  202: #  define NEXT_P1_5	do {KILLS GOTO(*(ip-1));} while(0)
  203: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  204: #endif
  205: 
  206: 
  207: #if THREADING_SCHEME==3
  208: #warning direct threading scheme 3: autoinc, low latency, cfa live
  209: #  define NEXT_P0
  210: #  define CFA		cfa
  211: #  define IP		(ip)
  212: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  213: #  define NEXT_INST	(*ip)
  214: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  215: #  define DEF_CA
  216: #  define NEXT_P1	do {cfa=*ip++;} while(0)
  217: #  define NEXT_P1_5	do {GOTO(cfa);} while(0)
  218: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  219: #endif
  220: 
  221: #if THREADING_SCHEME==4
  222: #warning direct threading scheme 4: autoinc, low latency, cfa dead
  223: #  define NEXT_P0
  224: #  define CFA		cfa
  225: #  define IP		(ip)
  226: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  227: #  define NEXT_INST	(*ip)
  228: #  define INC_IP(const_inc)	do { ip+=(const_inc);} while(0)
  229: #  define DEF_CA
  230: #  define NEXT_P1
  231: #  define NEXT_P1_5	do {KILLS GOTO(*(ip++));} while(0)
  232: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  233: #endif
  234: 
  235: #if THREADING_SCHEME==5
  236: #warning direct threading scheme 5: long latency, cfa live
  237: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
  238: #  define CFA		cfa1
  239: #  define MORE_VARS     Xt cfa1;
  240: #  define IP		(ip)
  241: #  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
  242: #  define NEXT_INST	(cfa)
  243: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  244: #  define DEF_CA
  245: #  define NEXT_P1	(ip++)
  246: #  define NEXT_P1_5	do {GOTO(cfa);} while(0)
  247: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  248: #endif
  249: 
  250: #if THREADING_SCHEME==6
  251: #warning direct threading scheme 6: long latency, cfa dead
  252: #  define NEXT_P0
  253: #  define CFA		cfa
  254: #  define IP		(ip)
  255: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  256: #  define NEXT_INST	(*ip)
  257: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  258: #  define DEF_CA
  259: #  define NEXT_P1	(ip++)
  260: #  define NEXT_P1_5	do {KILLS GOTO(*(ip-1));} while(0)
  261: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  262: #endif
  263: 
  264: 
  265: #if THREADING_SCHEME==7
  266: #warning direct threading scheme 7: low latency, cfa live
  267: #  define NEXT_P0
  268: #  define CFA		cfa
  269: #  define IP		(ip)
  270: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  271: #  define NEXT_INST	(*ip)
  272: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  273: #  define DEF_CA
  274: #  define NEXT_P1	do {cfa=*ip++;} while(0)
  275: #  define NEXT_P1_5	do {GOTO(cfa);} while(0)
  276: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  277: #endif
  278: 
  279: #if THREADING_SCHEME==8
  280: #warning direct threading scheme 8: cfa dead, i386 hack
  281: #  define NEXT_P0
  282: #  define CFA		cfa
  283: #  define IP		(ip)
  284: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  285: #  define NEXT_INST	(*IP)
  286: #  define INC_IP(const_inc)	do { ip+=(const_inc);} while(0)
  287: #  define DEF_CA
  288: #  define NEXT_P1	(ip++)
  289: #  define NEXT_P1_5	do {KILLS GOTO(*(ip-1));} while(0)
  290: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  291: #endif
  292: 
  293: #if THREADING_SCHEME==9
  294: #warning direct threading scheme 9: Power/PPC hack, long latency
  295: /* Power uses a prepare-to-branch instruction, and the latency between
  296:    this inst and the branch is 5 cycles on a PPC604; so we utilize this
  297:    to do some prefetching in between */
  298: #  define NEXT_P0
  299: #  define CFA		cfa
  300: #  define IP		ip
  301: #  define SET_IP(p)	do {ip=(p); next_cfa=*ip; NEXT_P0;} while(0)
  302: #  define NEXT_INST	(next_cfa)
  303: #  define INC_IP(const_inc)	do {next_cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  304: #  define DEF_CA	
  305: #  define NEXT_P1	do {cfa=next_cfa; ip++; next_cfa=*ip;} while(0)
  306: #  define NEXT_P1_5	do {GOTO(cfa);} while(0)
  307: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  308: #  define MORE_VARS	Xt next_cfa;
  309: #endif
  310: 
  311: #if THREADING_SCHEME==10
  312: #warning direct threading scheme 10: plain (no attempt at scheduling)
  313: #  define NEXT_P0
  314: #  define CFA		cfa
  315: #  define IP		(ip)
  316: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  317: #  define NEXT_INST	(*ip)
  318: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  319: #  define DEF_CA
  320: #  define NEXT_P1
  321: #  define NEXT_P1_5	do {cfa=*ip++; GOTO(cfa);} while(0)
  322: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  323: #endif
  324: 
  325: /* direct threaded */
  326: #else
  327: /* indirect THREADED  */
  328: 
  329: #ifndef THREADING_SCHEME
  330: #define THREADING_SCHEME 6
  331: #endif
  332: 
  333: #if THREADING_SCHEME==1
  334: #warning indirect threading scheme 1: autoinc, long latency, cisc
  335: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip++;} while(0)
  336: #  define CFA		cfa1
  337: #  define MORE_VARS     Xt cfa1;
  338: #  define IP		(ip-1)
  339: #  define SET_IP(p)	do {ip=(p); cfa=*ip++;} while(0)
  340: #  define NEXT_INST	(cfa)
  341: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  342: #  define DEF_CA
  343: #  define NEXT_P1
  344: #  define NEXT_P1_5	do {GOTO(*cfa);} while(0)
  345: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  346: #endif
  347: 
  348: #if THREADING_SCHEME==2
  349: #warning indirect threading scheme 2: autoinc, long latency
  350: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip++;} while(0)
  351: #  define CFA		cfa1
  352: #  define MORE_VARS     Xt cfa1;
  353: #  define IP		(ip-1)
  354: #  define SET_IP(p)	do {ip=(p); cfa=*ip++;} while(0)
  355: #  define NEXT_INST	(cfa)
  356: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  357: #  define DEF_CA	Label ca;
  358: #  define NEXT_P1	do {ca=*cfa;} while(0)
  359: #  define NEXT_P1_5	do {GOTO(ca);} while(0)
  360: #  define EXEC1(XT)	do {DEF_CA cfa=(XT); ca=*cfa; GOTO(ca);} while(0)
  361: #endif
  362: 
  363: 
  364: #if THREADING_SCHEME==3
  365: #warning indirect threading scheme 3: autoinc, low latency, cisc
  366: #  define NEXT_P0
  367: #  define CFA		cfa
  368: #  define IP		(ip)
  369: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  370: #  define NEXT_INST	(*ip)
  371: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  372: #  define DEF_CA
  373: #  define NEXT_P1
  374: #  define NEXT_P1_5	do {cfa=*ip++; GOTO(*cfa);} while(0)
  375: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  376: #endif
  377: 
  378: #if THREADING_SCHEME==4
  379: #warning indirect threading scheme 4: autoinc, low latency
  380: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip++;} while(0)
  381: #  define CFA		cfa1
  382: #  define MORE_VARS     Xt cfa1;
  383: #  define IP		(ip-1)
  384: #  define SET_IP(p)	do {ip=(p); cfa=*ip++;} while(0)
  385: #  define NEXT_INST	(cfa)
  386: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  387: #  define DEF_CA	Label ca;
  388: #  define NEXT_P1	do {ca=*cfa;} while(0)
  389: #  define NEXT_P1_5	do {GOTO(ca);} while(0)
  390: #  define EXEC1(XT)	do {DEF_CA cfa=(XT); ca=*cfa; GOTO(ca);} while(0)
  391: #endif
  392: 
  393: 
  394: #if THREADING_SCHEME==5
  395: #warning indirect threading scheme 5: long latency, cisc
  396: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
  397: #  define CFA		cfa1
  398: #  define MORE_VARS     Xt cfa1;
  399: #  define IP		(ip)
  400: #  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
  401: #  define NEXT_INST	(cfa)
  402: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  403: #  define DEF_CA
  404: #  define NEXT_P1	(ip++)
  405: #  define NEXT_P1_5	do {GOTO(*cfa);} while(0)
  406: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  407: #endif
  408: 
  409: #if THREADING_SCHEME==6
  410: #warning indirect threading scheme 6: long latency
  411: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
  412: #  define CFA		cfa1
  413: #  define MORE_VARS     Xt cfa1;
  414: #  define IP		(ip)
  415: #  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
  416: #  define NEXT_INST	(cfa)
  417: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  418: #  define DEF_CA	Label ca;
  419: #  define NEXT_P1	do {ip++; ca=*cfa;} while(0)
  420: #  define NEXT_P1_5	do {GOTO(ca);} while(0)
  421: #  define EXEC1(XT)	do {DEF_CA cfa=(XT); ca=*cfa; GOTO(ca);} while(0)
  422: #endif
  423: 
  424: #if THREADING_SCHEME==7
  425: #warning indirect threading scheme 7: low latency
  426: #  define NEXT_P0	do {cfa1=cfa; cfa=*ip;} while(0)
  427: #  define CFA		cfa1
  428: #  define MORE_VARS     Xt cfa1;
  429: #  define IP		(ip)
  430: #  define SET_IP(p)	do {ip=(p); cfa=*ip;} while(0)
  431: #  define NEXT_INST	(cfa)
  432: #  define INC_IP(const_inc)	do {cfa=IP[const_inc]; ip+=(const_inc);} while(0)
  433: #  define DEF_CA	Label ca;
  434: #  define NEXT_P1	do {ip++; ca=*cfa;} while(0)
  435: #  define NEXT_P1_5	do {GOTO(ca);} while(0)
  436: #  define EXEC1(XT)	do {DEF_CA cfa=(XT); ca=*cfa; GOTO(ca);} while(0)
  437: #endif
  438: 
  439: #if THREADING_SCHEME==8
  440: #warning indirect threading scheme 8: low latency,cisc
  441: #  define NEXT_P0
  442: #  define CFA		cfa
  443: #  define IP		(ip)
  444: #  define SET_IP(p)	do {ip=(p); NEXT_P0;} while(0)
  445: #  define NEXT_INST	(*ip)
  446: #  define INC_IP(const_inc)	do {ip+=(const_inc);} while(0)
  447: #  define DEF_CA
  448: #  define NEXT_P1
  449: #  define NEXT_P1_5	do {cfa=*ip++; GOTO(*cfa);} while(0)
  450: #  define EXEC1(XT)	do {cfa=(XT); GOTO(*cfa);} while(0)
  451: #endif
  452: 
  453: /* indirect threaded */
  454: #endif
  455: 
  456: #endif /* !defined(DOUBLY_INDIRECT) && !defined(NO_IP) */
  457: 

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