File:  [gforth] / gforth / Attic / alpha.h
Revision 1.8: download - view: text, annotated - select for diffs
Fri Jul 26 15:28:28 1996 UTC (27 years, 8 months ago) by anton
Branches: MAIN
CVS tags: HEAD
adapted DOES_CODE in alpha.h m68k.h mips.h power.h and sparc.h
worked around a bug in SunOS4 in prims2x.fs
fixed typo in main.c

    1: /* preliminary machine file for DEC Alpha
    2: 
    3:   Copyright (C) 1995 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., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: */
   21: 
   22: /* Be careful: long long on Alpha are 64 bit :-(( */
   23: #define LONG_LATENCY
   24: 
   25: #if !defined(USE_TOS) && !defined(USE_NO_TOS)
   26: #define USE_TOS
   27: #endif
   28: 
   29: #ifndef INDIRECT_THREADED
   30: #ifndef DIRECT_THREADED
   31: #define DIRECT_THREADED
   32: #endif
   33: #endif
   34: 
   35: #define FLUSH_ICACHE(addr,size)		asm("call_pal 0x86") /* imb (instruction-memory barrier) */
   36: 
   37: #include "32bit.h"
   38: 
   39: #ifdef DIRECT_THREADED
   40: #ifdef WORDS_BIGENDIAN
   41: #error Direct threading only supported for little-endian Alphas.
   42: /* big-endian Alphas still store instructions in little-endian format,
   43:    so you would have to reverse the instruction accesses in the following
   44: */
   45: #endif
   46: #if SIZEOF_CHAR_P != 8
   47: #error Direct threading only supported for Alphas with 64-bit Cells.
   48: /* some of the stuff below assumes that the first cell in a code field
   49:    can contain 2 instructions
   50: 
   51:    A simple way around this problem would be to have _alpha_docol
   52:    contain &&dodoes. This would slow down colon defs, however.
   53: 
   54:    Another way is to use a special DOES_HANDLER, like most other CPUs */
   55: #endif
   56: 
   57: #warning Direct threading for Alpha may not work with all gcc versions
   58: #warning CODE does not (yet) work on the Alpha with direct threading
   59: /* Currently CODE tries to put a jump to the PFA into the code field.
   60:    Since the PFA is far away from docol, the present code generated
   61:    for the jump does not work. The solution would be, of course, to do
   62:    away with this foolish jump.  ";CODE" is harder to get right,
   63:    however.
   64: */
   65: 
   66: typedef int Int32;
   67: typedef short Int16;
   68: 
   69: /* PFA gives the parameter field address corresponding to a cfa */
   70: #define PFA(cfa)	(((Cell *)cfa)+2)
   71: /* PFA1 is a special version for use just after a NEXT1 */
   72: /* the improvement here is that we may destroy cfa before using PFA1 */
   73: #define PFA1(cfa)       PFA(cfa)
   74: 
   75: /*
   76:    On the Alpha, code (in the text segment) typically cannot be
   77:    reached from the dictionary (in the data segment) with a normal
   78:    branch. It also usually takes too long (and too much space on
   79:    32-bit systems) to load the address as literal and jump indirectly.
   80:    
   81:    So, what we do is this: a pointer into our code (at docol, to be
   82:    exact) is kept in a register: _alpha_docol. When the inner
   83:    interpreter jumps to the word address of a variable etc., the
   84:    destination address is computed from that with a lda instruction
   85:    and stored in another register: _alpha_ca. Then an indirect jump
   86:    through _alpha_ca is performed. For docol, we need not compute
   87:    _alpha_ca first.
   88: 
   89:    How do we tell gcc all this? We declare the registers as variables:
   90:    _alpha_docol as explicit variable, to avoid spilling; _alpha_ca is
   91:    so short-lived, so it hopefully won't be spilled. A
   92:    pseudo-primitive cpu_dep is created with code that lets gcc's data
   93:    flow analysis know that _alpha_docol is used and that _alpha_ca may
   94:    be defined and used after any NEXT and before any primitive.  We
   95:    let gcc choose the register for _alpha_ca and simply change the
   96:    code gcc produces for the cpu_dep routine.
   97: */
   98: 
   99: #define CPU_DEP2	register Label _alpha_docol asm("$9")=&&docol; \
  100: 			register Label _alpha_ca;
  101: 
  102: #define CPU_DEP3	cpu_dep: asm("lda %0, 500(%1)":"=r"(_alpha_ca):"r"(_alpha_docol)); goto *_alpha_ca;
  103: 
  104: #define CPU_DEP1	(&&cpu_dep)
  105: 
  106: 
  107: /* CODE_ADDRESS is the address of the code jumped to through the code field */
  108: #define CODE_ADDRESS(wa)	({Int32 *_wa=(Int32 *)(wa); \
  109: 				    (_wa[0]&0xfc000000)==0x68000000 ? /*JMP?*/\
  110: 				    &&docol : \
  111: 				    &&docol+((Int16 *)_wa)[0]; })
  112: 
  113: #define _CPU_DEP_LABEL	(symbols[DOESJUMP])
  114: #define _DOCOL_LABEL	(symbols[DOCOL])
  115: 
  116: /* MAKE_CF creates an appropriate code field at the wa; ca is the code
  117:    address. For the Alpha, this is a lda followed by a jmp (or just a
  118:    jmp, if ca==&&docol).  We patch the jmp with a good hint (on the
  119:    21064A this saves 5 cycles!) */
  120: #define MAKE_CF(wa,ca)	({ \
  121: 			     Int32 *_wa=(Int32 *)(wa); \
  122: 			     Label _ca=(Label)(ca); \
  123: 			     if (ca==_DOCOL_LABEL)  \
  124: 			       _wa[0]=(((0x1a<<26)|(31<<21)|(9<<16))| \
  125: 				       (((((Cell)_ca)-((Cell)_wa)-4) & 0xffff)>>2)); \
  126: 			     else { \
  127: 			       _wa[0]=((((Int32 *)_CPU_DEP_LABEL)[0] & 0xffff0000)| \
  128: 				       ((((Cell)_ca)-((Cell)_DOCOL_LABEL)) & 0xffff)); \
  129: 			       _wa[1]=((((Int32 *)_CPU_DEP_LABEL)[1] & 0xffffc000)| \
  130: 				       (((((Cell)_ca)-((Cell)_wa)-8) & 0xffff)>>2));  \
  131: 			     } \
  132: 			})
  133: 
  134: /* this is the point where the does code for the word with the xt cfa
  135:    starts. Because the jump to the code field takes only one cell on
  136:    64-bit systems we can use the second cell of the cfa for storing
  137:    the does address */
  138: #define DOES_CODE(cfa) \
  139:      ({ Int32 *_wa=(cfa); \
  140: 	(_wa[0] == ((((Int32 *)_CPU_DEP_LABEL)[0] & 0xffff0000)| \
  141: 		    ((((Cell)&&dodoes)-((Cell)&&docol)) & 0xffff)) && \
  142: 	 (_wa[1]&0xffffc000) == (((Int32 *)_CPU_DEP_LABEL)[1] & 0xffffc000)) \
  143: 	? DOES_CODE1(_wa) : 0; })
  144: 
  145: /* this is a special version of DOES_CODE for use in dodoes */
  146: #define DOES_CODE1(cfa)	((Xt *)(((Cell *)(cfa))[1]))
  147: 
  148: /* the does handler resides between DOES> and the following Forth
  149:    code. Since the code-field jumps directly to dodoes, the
  150:    does-handler is not needed for the Alpha architecture */
  151: #define DOES_HANDLER_SIZE       (2*sizeof(Cell))
  152: #define MAKE_DOES_HANDLER(addr)   0
  153: 
  154: /* This makes a code field for a does-defined word. doesp is the
  155:    address of the does-code. On the Alpha, the code field consists of
  156:    a jump to dodoes and the address of the does code */
  157: #define MAKE_DOES_CF(cfa,doesp) ({Xt *_cfa = (Xt *)(cfa); \
  158: 				    MAKE_CF(_cfa, symbols[DODOES]); \
  159: 				    _cfa[1] = (doesp); })
  160: #endif
  161: 

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