File:  [gforth] / gforth / Attic / alpha.h
Revision 1.9: download - view: text, annotated - select for diffs
Wed Oct 2 09:48:55 1996 UTC (25 years ago) by anton
Branches: MAIN
CVS tags: v0-2-1, v0-2-0, HEAD
made path separator OS-dependent (';' for non-Unix)
renamed use-file to open-blocks
reintroduced FUZZ (for non-Unix)

    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 work on the Alpha with direct threading
   59: /* ;CODE puts a jump to the code after ;CODE into the defined
   60:    word. The code generated for the jump can only jump to targets near
   61:    docol (near means: within 32KB). Because the code is far from
   62:    docol, this does not work.
   63: 
   64:    Solution: let the code be: x=cfa[1]; goto *x;
   65:    */
   66: 
   67: typedef int Int32;
   68: typedef short Int16;
   69: 
   70: /* PFA gives the parameter field address corresponding to a cfa */
   71: #define PFA(cfa)	(((Cell *)cfa)+2)
   72: /* PFA1 is a special version for use just after a NEXT1 */
   73: /* the improvement here is that we may destroy cfa before using PFA1 */
   74: #define PFA1(cfa)       PFA(cfa)
   75: 
   76: /*
   77:    On the Alpha, code (in the text segment) typically cannot be
   78:    reached from the dictionary (in the data segment) with a normal
   79:    branch. It also usually takes too long (and too much space on
   80:    32-bit systems) to load the address as literal and jump indirectly.
   81:    
   82:    So, what we do is this: a pointer into our code (at docol, to be
   83:    exact) is kept in a register: _alpha_docol. When the inner
   84:    interpreter jumps to the word address of a variable etc., the
   85:    destination address is computed from that with a lda instruction
   86:    and stored in another register: _alpha_ca. Then an indirect jump
   87:    through _alpha_ca is performed. For docol, we need not compute
   88:    _alpha_ca first.
   89: 
   90:    How do we tell gcc all this? We declare the registers as variables:
   91:    _alpha_docol as explicit variable, to avoid spilling; _alpha_ca is
   92:    so short-lived, so it hopefully won't be spilled. A
   93:    pseudo-primitive cpu_dep is created with code that lets gcc's data
   94:    flow analysis know that _alpha_docol is used and that _alpha_ca may
   95:    be defined and used after any NEXT and before any primitive.  We
   96:    let gcc choose the register for _alpha_ca and simply change the
   97:    code gcc produces for the cpu_dep routine.
   98: */
   99: 
  100: #define CPU_DEP2	register Label _alpha_docol asm("$9")=&&docol; \
  101: 			register Label _alpha_ca;
  102: 
  103: #define CPU_DEP3	cpu_dep: asm("lda %0, 500(%1)":"=r"(_alpha_ca):"r"(_alpha_docol)); goto *_alpha_ca;
  104: 
  105: #define CPU_DEP1	(&&cpu_dep)
  106: 
  107: 
  108: /* CODE_ADDRESS is the address of the code jumped to through the code field */
  109: #define CODE_ADDRESS(wa)	({Int32 *_wa=(Int32 *)(wa); \
  110: 				    (_wa[0]&0xfc000000)==0x68000000 ? /*JMP?*/\
  111: 				    &&docol : \
  112: 				    &&docol+((Int16 *)_wa)[0]; })
  113: 
  114: #define _CPU_DEP_LABEL	(symbols[DOESJUMP])
  115: #define _DOCOL_LABEL	(symbols[DOCOL])
  116: 
  117: /* MAKE_CF creates an appropriate code field at the wa; ca is the code
  118:    address. For the Alpha, this is a lda followed by a jmp (or just a
  119:    jmp, if ca==&&docol).  We patch the jmp with a good hint (on the
  120:    21064A this saves 5 cycles!) */
  121: #define MAKE_CF(wa,ca)	({ \
  122: 			     Int32 *_wa=(Int32 *)(wa); \
  123: 			     Label _ca=(Label)(ca); \
  124: 			     if (ca==_DOCOL_LABEL)  \
  125: 			       _wa[0]=(((0x1a<<26)|(31<<21)|(9<<16))| \
  126: 				       (((((Cell)_ca)-((Cell)_wa)-4) & 0xffff)>>2)); \
  127: 			     else { \
  128: 			       _wa[0]=((((Int32 *)_CPU_DEP_LABEL)[0] & 0xffff0000)| \
  129: 				       ((((Cell)_ca)-((Cell)_DOCOL_LABEL)) & 0xffff)); \
  130: 			       _wa[1]=((((Int32 *)_CPU_DEP_LABEL)[1] & 0xffffc000)| \
  131: 				       (((((Cell)_ca)-((Cell)_wa)-8) & 0xffff)>>2));  \
  132: 			     } \
  133: 			})
  134: 
  135: /* this is the point where the does code for the word with the xt cfa
  136:    starts. Because the jump to the code field takes only one cell on
  137:    64-bit systems we can use the second cell of the cfa for storing
  138:    the does address */
  139: #define DOES_CODE(cfa) \
  140:      ({ Int32 *_wa=(cfa); \
  141: 	(_wa[0] == ((((Int32 *)_CPU_DEP_LABEL)[0] & 0xffff0000)| \
  142: 		    ((((Cell)&&dodoes)-((Cell)&&docol)) & 0xffff)) && \
  143: 	 (_wa[1]&0xffffc000) == (((Int32 *)_CPU_DEP_LABEL)[1] & 0xffffc000)) \
  144: 	? DOES_CODE1(_wa) : 0; })
  145: 
  146: /* this is a special version of DOES_CODE for use in dodoes */
  147: #define DOES_CODE1(cfa)	((Xt *)(((Cell *)(cfa))[1]))
  148: 
  149: /* the does handler resides between DOES> and the following Forth
  150:    code. Since the code-field jumps directly to dodoes, the
  151:    does-handler is not needed for the Alpha architecture */
  152: #define DOES_HANDLER_SIZE       (2*sizeof(Cell))
  153: #define MAKE_DOES_HANDLER(addr)   0
  154: 
  155: /* This makes a code field for a does-defined word. doesp is the
  156:    address of the does-code. On the Alpha, the code field consists of
  157:    a jump to dodoes and the address of the does code */
  158: #define MAKE_DOES_CF(cfa,doesp) ({Xt *_cfa = (Xt *)(cfa); \
  159: 				    MAKE_CF(_cfa, symbols[DODOES]); \
  160: 				    _cfa[1] = (doesp); })
  161: #endif
  162: 

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