File:  [gforth] / gforth / Attic / power.h
Revision 1.5: download - view: text, annotated - select for diffs
Fri Jul 26 16:16:55 1996 UTC (25 years ago) by anton
Branches: MAIN
CVS tags: v0-2-1, v0-2-0, HEAD
small fix

    1: /* This is the machine-specific part for the Power (incl. PPC) architecture
    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: #if !defined(USE_TOS) && !defined(USE_NO_TOS)
   23: #define USE_TOS
   24: #endif
   25: 
   26: #ifndef INDIRECT_THREADED
   27: #ifndef DIRECT_THREADED
   28: /* #define DIRECT_THREADED */
   29: #endif
   30: #endif
   31: 
   32: #include "32bit.h"
   33: 
   34: /* cache flush stuff */
   35: #warning If you get assembly errors, here is the reason why
   36: #define FLUSH_ICACHE(addr,size)   asm("icbi (%0); isync"::"b"(addr))
   37: /* this assumes size=4 */
   38: /* the mnemonics are for the PPC and the syntax is a wild guess; for
   39:    Power the mnemonic for the isync instruction is "ics" and I have
   40:    not found an equivalent for the icbi instruction in my reference.
   41: */
   42: 
   43: #ifdef DIRECT_THREADED
   44: #warning Direct threading for Power has not been tested
   45: 
   46: /* PFA gives the parameter field address corresponding to a cfa */
   47: #define PFA(cfa)	(((Cell *)cfa)+2)
   48: /* PFA1 is a special version for use just after a NEXT1 */
   49: /* the improvement here is that we may destroy cfa before using PFA1 */
   50: #define PFA1(cfa)       PFA(cfa)
   51: 
   52: /* I'll assume the code resides in the lower (or upper) 32M of the
   53:    address space and use absolute addressing in the jumps to the
   54:    handlers. This makes it possible to use the full address space for
   55:    direct threaded Forth (even on 64-bit PowerPCs). However, the
   56:    linker has to ensure that this really happens */
   57: 
   58: #define JUMP_TARGET_BITS 0
   59: /* assuming the code is in the lower 32M; if it is in the upper 32M,
   60:    define JUMP_TARGET_BITS as ~0x3ffffff */
   61: #define JUMP_MASK	0x3fffffc
   62: 
   63: /* CODE_ADDRESS is the address of the code jumped to through the code field */
   64: #define CODE_ADDRESS(cfa)	((Label)(((*(unsigned *)(cfa))&JUMP_MASK)|JUMP_TARGET_BITS))
   65: 
   66: /* MAKE_CF creates an appropriate code field at the cfa; ca is the
   67:    code address. For those familiar with assembly, this is a `ba'
   68:    instruction in both Power and PowerPC assembly languages */
   69: #define MAKE_CF(cfa,ca)	(*(long *)(cfa) = 0x48000002|(ca))
   70: 
   71: /* this is the point where the does code for the word with the xt cfa
   72:    starts. Since a branch is only a cell on Power, we can use the
   73:    second cell of the cfa for storing the does address */
   74: #define DOES_CODE(cfa) \
   75:      ({ unsigned *_cfa=(unsigned *)(cfa); \
   76: 	_cfa[0]==(0x48000002|&&docol) ? DOES_CODE1(_cfa) : 0; })
   77:    
   78: 
   79: 	DOES_CODE(label)
   80: /* this is a special version of DOES_CODE for use in dodoes */
   81: #define DOES_CODE1(cfa)	((Xt *)(((long *)(cfa))[1]))
   82: 
   83: /* the does handler resides between DOES> and the following Forth
   84:    code. Since the code-field jumps directly to dodoes, the
   85:    does-handler is not needed for the Power architecture */
   86: #define DOES_HANDLER_SIZE       8
   87: #define MAKE_DOES_HANDLER(addr)   0
   88: 
   89: /* This makes a code field for a does-defined word. doesp is the
   90:    address of the does-code. On the PPC, the code field consists of a
   91:    jump to dodoes and the address of the does code */
   92: #define MAKE_DOES_CF(cfa,doesp) ({Xt *_cfa = (Xt *)(cfa); \
   93: 				    MAKE_CF(_cfa, symbols[DODOES]); \
   94: 				    _cfa[1] = (doesp); })
   95: #endif

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