stella/src/yacc/YaccParser.cxx

375 lines
10 KiB
C++

//============================================================================
//
// SSSS tt lll lll
// SS SS tt ll ll
// SS tttttt eeee ll ll aaaa
// SSSS tt ee ee ll ll aa
// SS tt eeeeee ll ll aaaaa -- "An Atari 2600 VCS Emulator"
// SS SS tt ee ll ll aa aa
// SSSS ttt eeeee llll llll aaaaa
//
// Copyright (c) 1995-2020 by Bradford W. Mott, Stephen Anthony
// and the Stella Team
//
// See the file "License.txt" for information on usage and redistribution of
// this file, and for a DISCLAIMER OF ALL WARRANTIES.
//============================================================================
#include "Base.hxx"
#include "DebuggerExpressions.hxx"
#include "YaccParser.hxx"
namespace YaccParser {
#include <cstdio>
#include <cctype>
#include "y.tab.h"
static YYSTYPE result;
static string errMsg;
void yyerror(const char* e);
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wold-style-cast"
#pragma clang diagnostic ignored "-Wimplicit-fallthrough"
#pragma clang diagnostic ignored "-Wmissing-variable-declarations"
#include "y.tab.c"
#pragma clang diagnostic pop
#else
#include "y.tab.c"
#endif
enum class State {
DEFAULT,
IDENTIFIER,
OPERATOR,
SPACE
};
static State state = State::DEFAULT;
static const char *input, *c;
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
const string& errorMessage()
{
return errMsg;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Expression* getResult()
{
lastExp = nullptr;
return result.exp;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void setInput(const string& in)
{
input = c = in.c_str();
state = State::DEFAULT;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
int parse(const string& in)
{
lastExp = nullptr;
errMsg = "(no error)";
setInput(in);
return yyparse();
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// hand-rolled lexer. Hopefully faster than flex...
inline bool is_base_prefix(char x)
{
return ( (x=='\\' || x=='$' || x=='#') );
}
inline bool is_identifier(char x)
{
return ( (x>='0' && x<='9') ||
(x>='a' && x<='z') ||
(x>='A' && x<='Z') ||
x=='.' || x=='_' );
}
inline bool is_operator(char x)
{
return ( (x=='+' || x=='-' || x=='*' ||
x=='/' || x=='<' || x=='>' ||
x=='|' || x=='&' || x=='^' ||
x=='!' || x=='~' || x=='(' ||
x==')' || x=='=' || x=='%' ||
x=='[' || x==']' ) );
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// const_to_int converts a string into a number, in either the
// current base, or (if there's a base override) the selected base.
// Returns -1 on error, since negative numbers are the parser's
// responsibility, not the lexer's
int const_to_int(char* ch)
{
// what base is the input in?
Common::Base::Fmt format = Common::Base::format();
switch(*ch) {
case '\\':
format = Common::Base::Fmt::_2;
ch++;
break;
case '#':
format = Common::Base::Fmt::_10;
ch++;
break;
case '$':
format = Common::Base::Fmt::_16;
ch++;
break;
default: // not a base_prefix, use default base
break;
}
int ret = 0;
switch(format) {
case Common::Base::Fmt::_2:
while(*ch) {
if(*ch != '0' && *ch != '1')
return -1;
ret *= 2;
ret += (*ch - '0');
ch++;
}
return ret;
case Common::Base::Fmt::_10:
while(*ch) {
if(!isdigit(*ch))
return -1;
ret *= 10;
ret += (*ch - '0');
ch++;
}
return ret;
case Common::Base::Fmt::_16:
while(*ch) { // FIXME: error check!
if(!isxdigit(*ch))
return -1;
int dig = (*ch - '0');
if(dig > 9) dig = tolower(*ch) - 'a' + 10;
ret *= 16;
ret += dig;
ch++;
}
return ret;
default:
cerr << "INVALID BASE in lexer!" << endl;
return 0;
}
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// special methods that get Cart RAM/ROM internal state
CartMethod getCartSpecial(char* ch)
{
if(BSPF::equalsIgnoreCase(ch, "_bank"))
return &CartDebug::getPCBank;
else if(BSPF::equalsIgnoreCase(ch, "__lastread"))
return &CartDebug::lastReadBaseAddress;
else if(BSPF::equalsIgnoreCase(ch, "__lastwrite"))
return &CartDebug::lastWriteBaseAddress;
else
return nullptr;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// special methods that get e.g. CPU registers
CpuMethod getCpuSpecial(char* ch)
{
if(BSPF::equalsIgnoreCase(ch, "a"))
return &CpuDebug::a;
else if(BSPF::equalsIgnoreCase(ch, "x"))
return &CpuDebug::x;
else if(BSPF::equalsIgnoreCase(ch, "y"))
return &CpuDebug::y;
else if(BSPF::equalsIgnoreCase(ch, "pc"))
return &CpuDebug::pc;
else if(BSPF::equalsIgnoreCase(ch, "sp"))
return &CpuDebug::sp;
else if(BSPF::equalsIgnoreCase(ch, "c"))
return &CpuDebug::c;
else if(BSPF::equalsIgnoreCase(ch, "z"))
return &CpuDebug::z;
else if(BSPF::equalsIgnoreCase(ch, "n"))
return &CpuDebug::n;
else if(BSPF::equalsIgnoreCase(ch, "v"))
return &CpuDebug::v;
else if(BSPF::equalsIgnoreCase(ch, "d"))
return &CpuDebug::d;
else if(BSPF::equalsIgnoreCase(ch, "i"))
return &CpuDebug::i;
else if(BSPF::equalsIgnoreCase(ch, "b"))
return &CpuDebug::b;
else if(BSPF::equalsIgnoreCase(ch, "_icycles"))
return &CpuDebug::icycles;
else
return nullptr;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
// special methods that get TIA internal state
TiaMethod getTiaSpecial(char* ch)
{
if(BSPF::equalsIgnoreCase(ch, "_scan"))
return &TIADebug::scanlines;
if(BSPF::equalsIgnoreCase(ch, "_scycles"))
return &TIADebug::cyclesThisLine;
else if(BSPF::equalsIgnoreCase(ch, "_fcount"))
return &TIADebug::frameCount;
else if(BSPF::equalsIgnoreCase(ch, "_fcycles"))
return &TIADebug::frameCycles;
else if(BSPF::equalsIgnoreCase(ch, "_cyclesLo"))
return &TIADebug::cyclesLo;
else if(BSPF::equalsIgnoreCase(ch, "_cyclesHi"))
return &TIADebug::cyclesHi;
else if(BSPF::equalsIgnoreCase(ch, "_cclocks"))
return &TIADebug::clocksThisLine;
else if(BSPF::equalsIgnoreCase(ch, "_vsync"))
return &TIADebug::vsyncAsInt;
else if(BSPF::equalsIgnoreCase(ch, "_vblank"))
return &TIADebug::vblankAsInt;
else
return nullptr;
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
int yylex() {
static char idbuf[255]; // NOLINT (will be rewritten soon)
char o, p;
yylval.val = 0;
while(*c != '\0') {
switch(state) {
case State::SPACE:
yylval.val = 0;
if(isspace(*c)) {
c++;
} else if(is_identifier(*c) || is_base_prefix(*c)) {
state = State::IDENTIFIER;
} else if(is_operator(*c)) {
state = State::OPERATOR;
} else {
state = State::DEFAULT;
}
break;
case State::IDENTIFIER:
{
CartMethod cartMeth;
CpuMethod cpuMeth;
TiaMethod tiaMeth;
char *bufp = idbuf;
*bufp++ = *c++; // might be a base prefix
while(is_identifier(*c)) { // may NOT be base prefixes
*bufp++ = *c++;
}
*bufp = '\0';
state = State::DEFAULT;
// Note: specials (like "a" for accumulator) have priority over
// numbers. So "a" always means accumulator, not hex 0xa. User
// is welcome to use a base prefix ("$a"), or a capital "A",
// to mean 0xa.
// Also, labels have priority over specials, so Bad Things will
// happen if the user defines a label that matches one of
// the specials. Who would do that, though?
if(Debugger::debugger().cartDebug().getAddress(idbuf) > -1) {
yylval.Equate = idbuf;
return EQUATE;
} else if( (cpuMeth = getCpuSpecial(idbuf)) ) {
yylval.cpuMethod = cpuMeth;
return CPU_METHOD;
} else if( (cartMeth = getCartSpecial(idbuf)) ) {
yylval.cartMethod = cartMeth;
return CART_METHOD;
} else if( (tiaMeth = getTiaSpecial(idbuf)) ) {
yylval.tiaMethod = tiaMeth;
return TIA_METHOD;
} else if( Debugger::debugger().getFunctionDef(idbuf) != EmptyString ) {
yylval.DefinedFunction = idbuf;
return FUNCTION;
} else {
yylval.val = const_to_int(idbuf);
if(yylval.val >= 0)
return NUMBER;
else
return ERR;
}
}
case State::OPERATOR:
o = *c++;
if(!*c) return o;
if(isspace(*c)) {
state = State::SPACE;
return o;
} else if(is_identifier(*c) || is_base_prefix(*c)) {
state = State::IDENTIFIER;
return o;
} else {
state = State::DEFAULT;
p = *c++;
if(o == '>' && p == '=')
return GTE;
else if(o == '<' && p == '=')
return LTE;
else if(o == '!' && p == '=')
return NE;
else if(o == '=' && p == '=')
return EQ;
else if(o == '|' && p == '|')
return LOG_OR;
else if(o == '&' && p == '&')
return LOG_AND;
else if(o == '<' && p == '<')
return SHL;
else if(o == '>' && p == '>')
return SHR;
else {
c--;
return o;
}
}
// break; Never executed
case State::DEFAULT:
yylval.val = 0;
if(isspace(*c)) {
state = State::SPACE;
} else if(is_identifier(*c) || is_base_prefix(*c)) {
state = State::IDENTIFIER;
} else if(is_operator(*c)) {
state = State::OPERATOR;
} else {
yylval.val = *c++;
return yylval.val;
}
break;
}
}
return 0; // hit NUL, end of input.
}
} // namespace YaccParser