Annotation of gforth/vmgen-ex/mini-inst.vmg, revision 1.4

1.1       anton       1: \ mini.inst is generated automatically from mini-inst.vmg and mini-super.vmg
                      2: \ example .vmg file
                      3: 
1.4     ! anton       4: \ Copyright (C) 2001,2002,2003 Free Software Foundation, Inc.
1.1       anton       5: 
                      6: \ This file is part of Gforth.
                      7: 
                      8: \ Gforth is free software; you can redistribute it and/or
                      9: \ modify it under the terms of the GNU General Public License
                     10: \ as published by the Free Software Foundation; either version 2
                     11: \ of the License, or (at your option) any later version.
                     12: 
                     13: \ This program is distributed in the hope that it will be useful,
                     14: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
                     15: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     16: \ GNU General Public License for more details.
                     17: 
                     18: \ You should have received a copy of the GNU General Public License
                     19: \ along with this program; if not, write to the Free Software
                     20: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
                     21: 
                     22: 
                     23: \ WARNING: This file is processed by m4. Make sure your identifiers
                     24: \ don't collide with m4's (e.g. by undefining them).
                     25: 
                     26: 
                     27: \ comments start with "\ "
                     28: 
                     29: \ stack definitions:
                     30: \E stack data-stack sp Cell
                     31: 
                     32: \ stack prefix definitions
                     33: \E inst-stream stack-prefix #
                     34: 
                     35: \ type prefix definitions:
                     36: \E s" Cell"   single data-stack type-prefix i
                     37: \E s" char *" single data-stack type-prefix a
                     38: \E s" Inst *" single data-stack type-prefix target
                     39: 
                     40: \ simple VM instructions:
1.2       anton      41: add ( i1 i2 -- i )
1.1       anton      42: i = i1+i2;
                     43: 
                     44: sub ( i1 i2 -- i )
                     45: i = i1-i2;
                     46: 
                     47: mul ( i1 i2 -- i )
                     48: i = i1*i2;
                     49: 
                     50: and ( i1 i2 -- i )
                     51: i = i1 & i2;
                     52: 
                     53: or ( i1 i2 -- i )
                     54: i = i1 | i2;
                     55: 
                     56: lessthan ( i1 i2 -- i )
                     57: i = i1<i2;
                     58: 
                     59: equals ( i1 i2 -- i )
                     60: i = i1==i2;
                     61: 
                     62: not ( i1 -- i2 )
                     63: i2 = !i1;
                     64: 
                     65: negate ( i1 -- i2 )
                     66: i2 = -i1;
                     67: 
                     68: lit ( #i -- i )
                     69: 
                     70: drop ( i -- )
                     71: 
                     72: print ( i -- )
                     73: printf("%ld\n", i);
                     74: 
                     75: branch ( #target -- )
                     76: SET_IP(target);
                     77: 
                     78: zbranch ( #target i -- )
                     79: if (i==0) {
                     80:   SET_IP(target);
1.2       anton      81:   INST_TAIL;
1.1       anton      82: }
                     83: 
                     84: \  The stack is organized as follows:
                     85: \  The stack grows downwards; a stack usually looks like this:
                     86: 
                     87: \  higher addresses
                     88: \  --------------------- bottom of stack
                     89: \     locals of main
                     90: \     return address (points to VM code after call)
                     91: \  +->oldfp (NULL)
                     92: \  |  intermediate results (e.g., 1 for a call like 1+foo(...))
                     93: \  |  arguments passed to the called function
                     94: \  |  locals of the called function
                     95: \  |  return address (points to VM code after call)
                     96: \  +--oldfp                <-- fp
                     97: \     intermediate results <-- sp
                     98: \  ---------------------- top of stack
                     99: \  lower addresses
                    100: 
                    101: \ The following VM instructions also explicitly reference sp and
                    102: \ therefore may have to do something about spTOS caching.
                    103: 
                    104: call ( #target #iadjust -- targetret aoldfp )
                    105: /* IF_spTOS(sp[2] = spTOS);*/ /* unnecessary; vmgen inserts a flush anyway */
                    106: targetret = IP;
                    107: SET_IP(target);
                    108: aoldfp = fp;
                    109: sp = (Cell *)(((char *)sp)+iadjust);
                    110: fp = (char *)sp;
                    111: /* IF_spTOS(spTOS = sp[0]); */ /* dead, thus unnecessary; vmgen copies aoldfp there */
                    112: 
                    113: return ( #iadjust target afp i1 -- i2 )
                    114: /* IF_spTOS(sp[-2] = spTOS); */ /* unnecessary; that stack item is dead */
                    115: SET_IP(target);
                    116: sp = (Cell *)(((char *)sp)+iadjust);
                    117: fp = afp;
                    118: i2=i1;
                    119: /* IF_spTOS(spTOS = sp[0]); */ /* dead, thus unnecessary; vmgen copies i2 there */
                    120: 
                    121: \ loadlocal and storelocal access stack items below spTOS, so we can
                    122: \ ignore spTOS caching.
                    123: 
                    124: loadlocal ( #ioffset -- i )
                    125: i = *(Cell *)(fp+ioffset);
                    126: 
                    127: storelocal ( #ioffset i -- )
                    128: *(Cell *)(fp+ioffset) = i;
                    129: 
                    130: end ( i -- )
                    131: /* SUPER_END would increment the next BB count (because IP points there);
                    132:    this would be a problem if there is no following BB.
                    133:    Instead, we do the following to add an end point for the current BB: */
                    134: #ifdef VM_PROFILING
                    135: block_insert(IP); /* we also do this at compile time, so this is unnecessary */
                    136: #endif
                    137: return i;
                    138: 
                    139: include(mini-super.vmg)

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