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-rw-r--r--libacc/acc.c175
1 files changed, 89 insertions, 86 deletions
diff --git a/libacc/acc.c b/libacc/acc.c
index 052c351..a8505cd 100644
--- a/libacc/acc.c
+++ b/libacc/acc.c
@@ -38,16 +38,16 @@
static int currentToken;
static int currentTokenData;
-static int C;
+static int gCurrentTokenOperatorLevel;
static int currentChar;
-static int K;
-static int q;
-static int G;
+static int gEndOfFunctionTarget;
+static int gProgramCounter;
+static int gFunctionStackSize;
static int savedChar;
static char* pInProgressMacro;
static char* P;
static char* ac;
-static char* v;
+static char* gStringTable;
static char* pSymbolTable;
static char* M;
static char* R;
@@ -104,7 +104,7 @@ static void nextToken() {
}
nextChar();
}
- C = 0;
+ gCurrentTokenOperatorLevel = 0;
currentToken = currentChar;
if (isSymbolChar()) {
addToSymbolTable(' ');
@@ -155,8 +155,8 @@ static void nextToken() {
while (j = *(char*) e++) {
m = *(char*) e++;
currentTokenData = 0;
- while ((C = *(char*) e++ - 98) < 0)
- currentTokenData = currentTokenData * 64 + C + 64;
+ while ((gCurrentTokenOperatorLevel = *(char*) e++ - 98) < 0)
+ currentTokenData = currentTokenData * 64 + gCurrentTokenOperatorLevel + 64;
if (j == currentToken && (m == currentChar || m == 64)) {
if (m == currentChar) {
nextChar();
@@ -171,11 +171,11 @@ static void nextToken() {
/*
* Emit 1 to 4 bytes of code. Little-endian, doesn't emit high bytes that
- * are 0x0 or 0xff
+ * are 0x00 or 0xff
*/
static void emitCode(int g) {
while( g && g != -1) {
- *(char*) q++=g;
+ *(char*) gProgramCounter++=g;
g=g>>8;
}
}
@@ -184,16 +184,16 @@ static void fixupAddress(e) {
int g;
while( e) {
g=*(int*) e;
- *(int*) e=q-e-4;
+ *(int*) e=gProgramCounter-e-4;
e=g;
}
}
static int emitCodeWithImmediate( g, e) {
emitCode(g);
- *(int*) q = e;
- e = q;
- q = q + 4;
+ *(int*) gProgramCounter = e;
+ e = gProgramCounter;
+ gProgramCounter = gProgramCounter + 4;
return e;
}
@@ -205,41 +205,41 @@ static int emitBranch(e) {
return emitCodeWithImmediate(0xe9,e); /* Jump relative */
}
-static int S( j, e) {
- emitCode(0x0FC085); /* XADD 85 r/m8, r8 exchange and add */
+static int emitTest( j, e) {
+ emitCode(0x0FC085); /* 85 C0 FC TEST */
return emitCodeWithImmediate(0x84 + j, e); /* TEST */
}
-static void Z(e) {
- emitCode( 0xC139);
+static void emitSetCC(int condition) {
+ emitCode( 0xC139); /* 39 C1 CMP */
emitLoadAccumulatorImmediate(0);
- emitCode( 0x0F);
- emitCode( e+0x90);
- emitCode( 0xC0);
+ emitCode( 0x0F); /* Two byte opcode prefix */
+ emitCode( condition+0x90); /* Set byte on condition (controlled by e) */
+ emitCode( 0xC0); /* I think this is part of the SETcc instruction */
}
-static void N( j, e) {
- emitCode(j + 0x83);
+static void emitNumericOp( int op, int e) {
+ emitCode(op + 0x83);
emitCodeWithImmediate((e < 512) << 7 | 5, e);
}
-static void T (int j) {
+static void parseTerminal (int level) {
int g,e,m,aa;
g=1;
if( currentToken == '"') {
- emitLoadAccumulatorImmediate(v);
+ emitLoadAccumulatorImmediate(gStringTable);
while( currentChar != '"') {
unescapeCurrentChar ();
- *(char*) v++=currentChar;
+ *(char*) gStringTable++=currentChar;
nextChar ();
}
- *(char*) v=0;
- v= (char*) (((int)v) +4&-4);
+ *(char*) gStringTable=0;
+ gStringTable= (char*) (((int)gStringTable) +4&-4);
nextChar();
nextToken();
}
else {
- aa=C;
+ aa=gCurrentTokenOperatorLevel;
m= currentTokenData;
e=currentToken;
nextToken();
@@ -247,9 +247,9 @@ static void T (int j) {
emitLoadAccumulatorImmediate(m);
}
else if( aa == 2) {
- T(0);
- emitCodeWithImmediate(0xB9,0);
- if( e == '!')Z(m);
+ parseTerminal(0);
+ emitCodeWithImmediate(0xB9,0); /* MOV r1, immediate */
+ if( e == '!')emitSetCC(m);
else emitCode( m);
}
else if( e == '(') {
@@ -269,36 +269,36 @@ static void T (int j) {
e=0;
}
nextToken();
- T(0);
+ parseTerminal(0);
if( currentToken == '=') {
nextToken();
- emitCode( 0x50);
+ emitCode( 0x50); /* PUSH r0 */
parseExpression ();
- emitCode( 0x59);
- emitCode( 0x188 + (e == TOKEN_INT));
+ emitCode( 0x59); /* POP r1 */
+ emitCode( 0x188 + (e == TOKEN_INT)); /* 88 01 MOV */
}
else if( e) {
- if( e == TOKEN_INT)emitCode( 0x8B);
- else emitCode( 0xBE0F);
- q++;
+ if( e == TOKEN_INT)emitCode( 0x8B); /* MOV */
+ else emitCode( 0xBE0F); /* 0F BE MOVSX move with sign extension */
+ gProgramCounter++;
}
}
else if( e == '&') {
- N(10,*(int*) currentToken);
+ emitNumericOp(10,*(int*) currentToken); /* 8D LEA */
nextToken();
}
else {
g=*(int*) e;
if(!g)g=dlsym(0,M);
- if( currentToken == '=' & j) {
+ if( currentToken == '=' & level) {
nextToken();
parseExpression ();
- N(6,g);
+ emitNumericOp(6,g); /* 89 MOV */
}
else if( currentToken!= '(') {
- N(8,g);
- if( C == 11) {
- N(0,g);
+ emitNumericOp(8,g); /* 8B MOV sreg */
+ if( gCurrentTokenOperatorLevel == 11) {
+ emitNumericOp(0,g); /* 83 ADD */
emitCode( currentTokenData);
nextToken();
}
@@ -306,45 +306,45 @@ static void T (int j) {
}
}
if( currentToken == '(') {
- if( g == 1)emitCode( 0x50);
- m= emitCodeWithImmediate(0xEC81,0);
+ if( g == 1)emitCode( 0x50); /* push */
+ m= emitCodeWithImmediate(0xEC81,0); /* 81 EC Cmp ?? */
nextToken();
- j=0;
+ level=0;
while( currentToken!= ')') {
parseExpression ();
- emitCodeWithImmediate(0x248489,j);
+ emitCodeWithImmediate(0x248489,level); /* 89 84 24 MOV sp + level*/
if( currentToken == ',')nextToken();
- j=j +4;
+ level=level +4;
}
- *(int*) m= j;
+ *(int*) m= level;
nextToken();
if(!g) {
e=e +4;
- *(int*) e=emitCodeWithImmediate(0xE8,*(int*) e);
+ *(int*) e=emitCodeWithImmediate(0xE8,*(int*) e); /* Call */
}
else if( g == 1) {
- emitCodeWithImmediate(0x2494FF,j);
- j=j +4;
+ emitCodeWithImmediate(0x2494FF,level); /* FF 94 24 */
+ level=level +4;
}
else {
- emitCodeWithImmediate(0xE8,g-q-5);
+ emitCodeWithImmediate(0xE8,g-gProgramCounter-5); /* CALL */
}
- if( j)emitCodeWithImmediate(0xC481,j);
+ if( level)emitCodeWithImmediate(0xC481,level); /* 81 C4 adjust stack pointer */
}
}
static void parseBinaryOp (int level) {
int e,g,m;
- if( level--== 1)T(1);
+ if( level--== 1)parseTerminal(1);
else {
parseBinaryOp (level);
m= 0;
- while( level == C) {
+ while( level == gCurrentTokenOperatorLevel) {
g=currentToken;
e=currentTokenData;
nextToken();
if( level>8) {
- m= S(e,m);
+ m= emitTest(e,m);
parseBinaryOp (level);
}
else {
@@ -352,18 +352,18 @@ static void parseBinaryOp (int level) {
parseBinaryOp (level);
emitCode( 0x59);
if( level == 4 | level == 5) {
- Z(e);
+ emitSetCC(e);
}
else {
emitCode( e);
- if( g == '%')emitCode( 0x92);
+ if( g == '%')emitCode( 0x92); /* XCHG */
}
}
}
if( m&&level>8) {
- m= S(e,m);
+ m= emitTest(e,m);
emitLoadAccumulatorImmediate(e^1);
- emitBranch(5);
+ emitBranch(5); /* Jump relative +5 */
fixupAddress(m);
emitLoadAccumulatorImmediate(e);
}
@@ -374,9 +374,9 @@ static void parseExpression() {
parseBinaryOp(11);
}
-static int U() {
+static int parseExpressionEmitTest() {
parseExpression();
- return S(0, 0);
+ return emitTest(0, 0);
}
static void parseStatement (int* pBreakTarget) {
@@ -384,7 +384,7 @@ static void parseStatement (int* pBreakTarget) {
if( currentToken == TOKEN_IF) {
nextToken();
nextToken();
- m= U ();
+ m= parseExpressionEmitTest ();
nextToken();
parseStatement (pBreakTarget);
if( currentToken == TOKEN_ELSE) {
@@ -403,27 +403,27 @@ static void parseStatement (int* pBreakTarget) {
nextToken();
nextToken();
if( e == TOKEN_WHILE) {
- g=q;
- m= U ();
+ g=gProgramCounter;
+ m= parseExpressionEmitTest ();
}
else {
if( currentToken != ';')parseExpression ();
nextToken();
- g=q;
+ g=gProgramCounter;
m= 0;
- if( currentToken != ';')m= U ();
+ if( currentToken != ';')m= parseExpressionEmitTest ();
nextToken();
if( currentToken!= ')') {
e=emitBranch(0);
parseExpression ();
- emitBranch(g-q-5);
+ emitBranch(g-gProgramCounter-5);
fixupAddress(e);
g=e +4;
}
}
nextToken();
parseStatement(&m);
- emitBranch(g-q-5);
+ emitBranch(g-gProgramCounter-5);
fixupAddress(m);
}
else if( currentToken == '{') {
@@ -436,7 +436,7 @@ static void parseStatement (int* pBreakTarget) {
if( currentToken == TOKEN_RETURN) {
nextToken();
if( currentToken != ';') parseExpression();
- K=emitBranch(K);
+ gEndOfFunctionTarget=emitBranch(gEndOfFunctionTarget);
}
else if( currentToken == TOKEN_BREAK) {
nextToken();
@@ -454,12 +454,12 @@ static void parseDeclarations (int isLocal) {
nextToken();
while( currentToken != ';') {
if( isLocal ) {
- G=G +4;
- *(int*) currentToken=-G;
+ gFunctionStackSize=gFunctionStackSize +4;
+ *(int*) currentToken=-gFunctionStackSize;
}
else {
- *(char**) currentToken = v;
- v=v +4;
+ *(char**) currentToken = gStringTable;
+ gStringTable=gStringTable +4;
}
nextToken();
if( currentToken == ',')nextToken();
@@ -468,7 +468,7 @@ static void parseDeclarations (int isLocal) {
}
else {
fixupAddress(*(int*)(currentToken + 4));
- *(int*) currentToken=q;
+ *(int*) currentToken=gProgramCounter;
nextToken();
nextToken();
m= 8;
@@ -479,13 +479,13 @@ static void parseDeclarations (int isLocal) {
if( currentToken == ',')nextToken();
}
nextToken();
- K=G=0;
- emitCode( 0xE58955);
- m= emitCodeWithImmediate(0xEC81,0);
+ gEndOfFunctionTarget=gFunctionStackSize=0;
+ emitCode( 0xE58955); /* 55 89 E5 PUSH */
+ m= emitCodeWithImmediate(0xEC81,0); /* 81 EC */
parseStatement(0);
- fixupAddress(K);
- emitCode( 0xC3C9);
- *(int*) m= G;
+ fixupAddress(gEndOfFunctionTarget);
+ emitCode( 0xC3C9); /* C9 C3 LEAVE */
+ *(int*) m= gFunctionStackSize;
}
}
}
@@ -503,9 +503,9 @@ int main( int argc, char** argv) {
}
pSymbolTable = strcpy(R = calloc(1, 99999),
" int if else while break return for define main ") + 48;
- v = calloc(1, 99999);
+ gStringTable = calloc(1, 99999);
ac = calloc(1, 99999);
- q = (int) ac;
+ gProgramCounter = (int) ac;
P = calloc(1, 99999);
nextChar();
nextToken();
@@ -516,6 +516,9 @@ int main( int argc, char** argv) {
fwrite(P, 1, 99999, stdout);
return 0;
#else
+ /* Look up the address of "main" in the symbol table and call it.
+ * We put main in at a known offset, so we know the address.
+ */
return (*(int(*)()) *(int*) (P + 592))(argc, argv);
#endif
}
generated by cgit v1.1 at 2025-11-26 14:00:36 +0000