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all jumps have byte variants; WHILE optimization

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This commit is contained in:
Roberto Ierusalimschy
1997-10-01 17:05:34 -03:00
parent eb617df2d8
commit 28d47a0aaa
3 changed files with 129 additions and 79 deletions
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133
lua.stx
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@@ -1,6 +1,6 @@
%{
/*
** $Id: lua.stx,v 1.5 1997/09/24 19:43:11 roberto Exp roberto $
** $Id: lua.stx,v 1.6 1997/09/26 15:02:26 roberto Exp roberto $
** Syntax analizer and code generator
** See Copyright Notice in lua.h
*/
@@ -28,6 +28,9 @@ int luaY_parse (void);
#define free luaM_free
/* size of a "normal" jump instruction: OpCode + 1 byte */
#define JMPSIZE 2
/* maximum number of local variables */
#define MAXLOCALS 32
@@ -85,11 +88,32 @@ void luaY_error (char *s)
}
static void code_byte (Byte c)
static void check_pc (int n)
{
if (currState->pc >= currState->maxcode)
if (currState->pc+n > currState->maxcode)
currState->maxcode = luaM_growvector(&currState->f->code,
currState->maxcode, Byte, codeEM, MAX_INT);
}
static void movecode_up (int d, int s, int n)
{
while (n--)
currState->f->code[d+n] = currState->f->code[s+n];
}
static void movecode_down (int d, int s, int n)
{
int i;
for (i=0; i<n; i++)
currState->f->code[d+i] = currState->f->code[s+i];
}
static void code_byte (Byte c)
{
check_pc(1);
currState->f->code[currState->pc++] = c;
}
@@ -103,19 +127,36 @@ static void code_word_at (int pc, int n)
}
static void fix_jump (int pc, OpCode op, int n)
static void code_word (int n)
{
currState->f->code[pc] = op;
code_word_at(pc+1, n);
check_pc(2);
currState->pc += 2;
code_word_at(currState->pc-2, n);
}
static void code_word (int n)
static int fix_opcode (int pc, OpCode op, int n)
{
if (n > MAX_WORD)
luaY_error("construction too big; unable to compile");
code_byte(n&0xFF);
code_byte(n>>8);
if (n <= 255) {
currState->f->code[pc] = op;
currState->f->code[pc+1] = n;
return 0;
}
else {
check_pc(1); /* open space */
movecode_up(pc+1, pc, currState->pc-pc);
currState->pc++;
currState->f->code[pc] = op+1; /* opcode must be word variant */
code_word_at(pc+1, n);
return 1;
}
}
static int fix_jump (int pc, OpCode op, int n)
{
n -= pc+1; /* jump is relative to position following jump opcode */
if (n > 255) n++; /* jump must be 1 bigger */
return fix_opcode(pc, op, n);
}
@@ -462,14 +503,14 @@ static int lua_codestore (int i, int left)
static void codeIf (int thenAdd, int elseAdd)
{
int elseinit = elseAdd+sizeof(Word)+1;
int elseinit = elseAdd+JMPSIZE;
if (currState->pc == elseinit) { /* no else part */
currState->pc -= sizeof(Word)+1;
currState->pc -= JMPSIZE;
elseinit = currState->pc;
}
else
fix_jump(elseAdd, JMP, currState->pc-(elseAdd+1));
fix_jump(thenAdd, IFFJMP, elseinit-(thenAdd+1));
elseinit += fix_jump(elseAdd, JMPB, currState->pc);
fix_jump(thenAdd, IFFJMPB, elseinit);
}
@@ -593,7 +634,7 @@ TProtoFunc *luaY_parser (ZIO *z, char *chunkname)
%token <vReal> NUMBER
%token <pTStr> NAME STRING
%type <vInt> PrepJump, PrepJumpPop, PrepJumpSC
%type <vInt> SaveWord, cond, GetPC, SaveWordPop, SaveWordPush
%type <vLong> exprlist, exprlist1 /* if > 0, points to function return
counter (which has list length); if <= 0, -list lenght */
%type <vLong> functioncall, expr /* if != 0, points to function return
@@ -628,18 +669,24 @@ statlist : /* empty */
sc : /* empty */ | ';' ;
stat : IF expr1 THEN PrepJumpPop block PrepJump elsepart END
{ codeIf($4, $6); }
stat : IF cond THEN block SaveWord elsepart END
{ codeIf($2, $5); }
| WHILE {$<vInt>$=currState->pc;} expr1 DO PrepJumpPop block END
{
code_opborw(UPJMPB, currState->pc+1 - ($<vInt>2), 0);
fix_jump($5, IFFJMP, currState->pc - ($5+1));
}
| WHILE GetPC cond DO block END
{{
int expsize = $3-$2;
int newpos = $2+JMPSIZE;
check_pc(expsize);
memcpy(&currState->f->code[currState->pc],
&currState->f->code[$2], expsize);
movecode_down($2, $3, currState->pc-$2);
newpos += fix_jump($2, JMPB, currState->pc-expsize);
code_opborw(IFTUPJMPB, currState->pc+1 - newpos, 0);
}}
| REPEAT {$<vInt>$=currState->pc;} block UNTIL expr1
| REPEAT GetPC block UNTIL expr1
{
code_opborw(IFFUPJMPB, currState->pc+1 - ($<vInt>2), -1);
code_opborw(IFFUPJMPB, currState->pc+1 - $2, -1);
}
| varlist1 '=' exprlist1
@@ -687,8 +734,8 @@ body : '(' parlist ')' chunk END { $$ = close_func(); }
elsepart : /* empty */
| ELSE block
| ELSEIF expr1 THEN PrepJumpPop block PrepJump elsepart
{ codeIf($4, $6); }
| ELSEIF cond THEN block SaveWord elsepart
{ codeIf($2, $5); }
;
ret : /* empty */
@@ -699,19 +746,19 @@ ret : /* empty */
}
;
PrepJump : /* empty */
{
$$ = currState->pc;
code_byte(0); /* open space */
code_word(0);
}
;
PrepJumpSC : /* empty */
{ $$ = currState->pc; code_opcode(0, -1); code_byte(0); }
GetPC : /* empty */ { $$ = currState->pc; }
;
PrepJumpPop : PrepJump { $$ = $1; deltastack(-1); /* pop condition */ }
SaveWord : GetPC { $$ = $1; code_word(0); /* open space */ }
;
SaveWordPop : SaveWord { $$ = $1; deltastack(-1); /* pop condition */ }
;
SaveWordPush : SaveWord { $$ = $1; deltastack(1); /* push a value */ }
;
cond : expr1 SaveWordPop { $$ = $2; }
;
expr1 : expr { adjust_functioncall($1, 1); }
@@ -739,14 +786,11 @@ expr : '(' expr ')' { $$ = $2; }
| NIL {code_opcode(PUSHNIL, 1); $$ = 0; }
| functioncall { $$ = $1; }
| FUNCTION { init_func(); } body { func_onstack($3); $$ = 0; }
| expr1 AND PrepJumpSC expr1 { code_shortcircuit(ONFJMP, $3); $$ = 0; }
| expr1 OR PrepJumpSC expr1 { code_shortcircuit(ONTJMP, $3); $$ = 0; }
| expr1 AND SaveWordPop expr1 { code_shortcircuit(ONFJMP, $3); $$ = 0; }
| expr1 OR SaveWordPop expr1 { code_shortcircuit(ONTJMP, $3); $$ = 0; }
;
table :
{ $<vInt>$ = currState->pc+1; code_opw(CREATEARRAY, 0, 1); }
'{' fieldlist '}'
{ code_word_at($<vInt>1, $3); }
table : '{' SaveWordPush fieldlist '}' { fix_opcode($2, CREATEARRAYB, $3); }
;
functioncall : funcvalue funcParams
@@ -892,3 +936,4 @@ decinit : /* empty */ { $$ = 0; }
;
%%