/*****************************************************************************/
/*                                                                           */
/*                                codeinfo.c                                 */
/*                                                                           */
/*                  Additional information about 6502 code                   */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2001-2012, Ullrich von Bassewitz                                      */
/*                Roemerstrasse 52                                           */
/*                D-70794 Filderstadt                                        */
/* EMail:         uz@cc65.org                                                */
/*                                                                           */
/*                                                                           */
/* This software is provided 'as-is', without any expressed or implied       */
/* warranty.  In no event will the authors be held liable for any damages    */
/* arising from the use of this software.                                    */
/*                                                                           */
/* Permission is granted to anyone to use this software for any purpose,     */
/* including commercial applications, and to alter it and redistribute it    */
/* freely, subject to the following restrictions:                            */
/*                                                                           */
/* 1. The origin of this software must not be misrepresented; you must not   */
/*    claim that you wrote the original software. If you use this software   */
/*    in a product, an acknowledgment in the product documentation would be  */
/*    appreciated but is not required.                                       */
/* 2. Altered source versions must be plainly marked as such, and must not   */
/*    be misrepresented as being the original software.                      */
/* 3. This notice may not be removed or altered from any source              */
/*    distribution.                                                          */
/*                                                                           */
/*****************************************************************************/



#include <stdlib.h>
#include <string.h>

/* common */
#include "chartype.h"
#include "coll.h"
#include "debugflag.h"

/* cc65 */
#include "codeent.h"
#include "codeseg.h"
#include "datatype.h"
#include "error.h"
#include "reginfo.h"
#include "symtab.h"
#include "codeinfo.h"



/*****************************************************************************/
/*                                   Data                                    */
/*****************************************************************************/



/* Table with the compare suffixes */
static const char CmpSuffixTab [][4] = {
    "eq", "ne", "gt", "ge", "lt", "le", "ugt", "uge", "ult", "ule"
};

/* Table listing the function names and code info values for known internally
 * used functions. This table should get auto-generated in the future.
 */
typedef struct FuncInfo FuncInfo;
struct FuncInfo {
    const char*     Name;       /* Function name */
    unsigned short  Use;        /* Register usage */
    unsigned short  Chg;        /* Changed/destroyed registers */
};

/* Note for the shift functions: Shifts are done modulo 32, so all shift
 * routines are marked to use only the A register. The remainder is ignored
 * anyway.
 */
static const FuncInfo FuncInfoTable[] = {
    { "addeq0sp",       REG_AX,               REG_AXY                        },
    { "addeqysp",       REG_AXY,              REG_AXY                        },
    { "addysp",         REG_Y,                REG_NONE                       },
    { "aslax1",         REG_AX,               REG_AX | REG_TMP1              },
    { "aslax2",         REG_AX,               REG_AX | REG_TMP1              },
    { "aslax3",         REG_AX,               REG_AX | REG_TMP1              },
    { "aslax4",         REG_AX,               REG_AX | REG_TMP1              },
    { "aslaxy",         REG_AXY,              REG_AXY | REG_TMP1             },
    { "asleax1",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asleax2",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asleax3",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asleax4",        REG_EAX,              REG_EAXY | REG_TMP1            },
    { "asrax1",         REG_AX,               REG_AX | REG_TMP1              },
    { "asrax2",         REG_AX,               REG_AX | REG_TMP1              },
    { "asrax3",         REG_AX,               REG_AX | REG_TMP1              },
    { "asrax4",         REG_AX,               REG_AX | REG_TMP1              },
    { "asraxy",         REG_AXY,              REG_AXY | REG_TMP1             },
    { "asreax1",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asreax2",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asreax3",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "asreax4",        REG_EAX,              REG_EAXY | REG_TMP1            },
    { "bnega",          REG_A,                REG_AX                         },
    { "bnegax",         REG_AX,               REG_AX                         },
    { "bnegeax",        REG_EAX,              REG_EAX                        },
    { "booleq",         REG_NONE,             REG_AX                         },
    { "boolge",         REG_NONE,             REG_AX                         },
    { "boolgt",         REG_NONE,             REG_AX                         },
    { "boolle",         REG_NONE,             REG_AX                         },
    { "boollt",         REG_NONE,             REG_AX                         },
    { "boolne",         REG_NONE,             REG_AX                         },
    { "booluge",        REG_NONE,             REG_AX                         },
    { "boolugt",        REG_NONE,             REG_AX                         },
    { "boolule",        REG_NONE,             REG_AX                         },
    { "boolult",        REG_NONE,             REG_AX                         },
    { "callax",         REG_AX,               REG_ALL                        },
    { "complax",        REG_AX,               REG_AX                         },
    { "decax1",         REG_AX,               REG_AX                         },
    { "decax2",         REG_AX,               REG_AX                         },
    { "decax3",         REG_AX,               REG_AX                         },
    { "decax4",         REG_AX,               REG_AX                         },
    { "decax5",         REG_AX,               REG_AX                         },
    { "decax6",         REG_AX,               REG_AX                         },
    { "decax7",         REG_AX,               REG_AX                         },
    { "decax8",         REG_AX,               REG_AX                         },
    { "decaxy",         REG_AXY,              REG_AX | REG_TMP1              },
    { "deceaxy",        REG_EAXY,             REG_EAX                        },
    { "decsp1",         REG_NONE,             REG_Y                          },
    { "decsp2",         REG_NONE,             REG_A                          },
    { "decsp3",         REG_NONE,             REG_A                          },
    { "decsp4",         REG_NONE,             REG_A                          },
    { "decsp5",         REG_NONE,             REG_A                          },
    { "decsp6",         REG_NONE,             REG_A                          },
    { "decsp7",         REG_NONE,             REG_A                          },
    { "decsp8",         REG_NONE,             REG_A                          },
    { "incax1",         REG_AX,               REG_AX                         },
    { "incax2",         REG_AX,               REG_AX                         },
    { "incax3",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incax4",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incax5",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incax6",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incax7",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incax8",         REG_AX,               REG_AXY | REG_TMP1             },
    { "incaxy",         REG_AXY,              REG_AXY | REG_TMP1             },
    { "incsp1",         REG_NONE,             REG_NONE                       },
    { "incsp2",         REG_NONE,             REG_Y                          },
    { "incsp3",         REG_NONE,             REG_Y                          },
    { "incsp4",         REG_NONE,             REG_Y                          },
    { "incsp5",         REG_NONE,             REG_Y                          },
    { "incsp6",         REG_NONE,             REG_Y                          },
    { "incsp7",         REG_NONE,             REG_Y                          },
    { "incsp8",         REG_NONE,             REG_Y                          },
    { "laddeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
    { "laddeq0sp",      REG_EAX,              REG_EAXY                       },
    { "laddeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
    { "laddeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
    { "laddeqysp",      REG_EAXY,             REG_EAXY                       },
    { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
    { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
    { "ldax0sp",        REG_NONE,             REG_AXY                        },
    { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
    { "ldaxidx",        REG_AXY,              REG_AXY | REG_PTR1             },
    { "ldaxysp",        REG_Y,                REG_AXY                        },
    { "ldeax0sp",       REG_NONE,             REG_EAXY                       },
    { "ldeaxi",         REG_AX,               REG_EAXY | REG_PTR1            },
    { "ldeaxidx",       REG_AXY,              REG_EAXY | REG_PTR1            },
    { "ldeaxysp",       REG_Y,                REG_EAXY                       },
    { "leaa0sp",        REG_A,                REG_AX                         },
    { "leaaxsp",        REG_AX,               REG_AX                         },
    { "lsubeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
    { "lsubeq0sp",      REG_EAX,              REG_EAXY                       },
    { "lsubeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
    { "lsubeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
    { "lsubeqysp",      REG_EAXY,             REG_EAXY                       },
    { "mulax10",        REG_AX,               REG_AX | REG_PTR1              },
    { "mulax3",         REG_AX,               REG_AX | REG_PTR1              },
    { "mulax5",         REG_AX,               REG_AX | REG_PTR1              },
    { "mulax6",         REG_AX,               REG_AX | REG_PTR1              },
    { "mulax7",         REG_AX,               REG_AX | REG_PTR1              },
    { "mulax9",         REG_AX,               REG_AX | REG_PTR1              },
    { "negax",          REG_AX,               REG_AX                         },
    { "push0",          REG_NONE,             REG_AXY                        },
    { "push0ax",        REG_AX,               REG_Y | REG_SREG               },
    { "push1",          REG_NONE,             REG_AXY                        },
    { "push2",          REG_NONE,             REG_AXY                        },
    { "push3",          REG_NONE,             REG_AXY                        },
    { "push4",          REG_NONE,             REG_AXY                        },
    { "push5",          REG_NONE,             REG_AXY                        },
    { "push6",          REG_NONE,             REG_AXY                        },
    { "push7",          REG_NONE,             REG_AXY                        },
    { "pusha",          REG_A,                REG_Y                          },
    { "pusha0",         REG_A,                REG_XY                         },
    { "pusha0sp",       REG_NONE,             REG_AY                         },
    { "pushaFF",        REG_A,                REG_Y                          },
    { "pushax",         REG_AX,               REG_Y                          },
    { "pushaysp",       REG_Y,                REG_AY                         },
    { "pushc0",         REG_NONE,             REG_A | REG_Y                  },
    { "pushc1",         REG_NONE,             REG_A | REG_Y                  },
    { "pushc2",         REG_NONE,             REG_A | REG_Y                  },
    { "pusheax",        REG_EAX,              REG_Y                          },
    { "pushl0",         REG_NONE,             REG_AXY                        },
    { "pushw",          REG_AX,               REG_AXY | REG_PTR1             },
    { "pushw0sp",       REG_NONE,             REG_AXY                        },
    { "pushwidx",       REG_AXY,              REG_AXY | REG_PTR1             },
    { "pushwysp",       REG_Y,                REG_AXY                        },
    { "regswap",        REG_AXY,              REG_AXY | REG_TMP1             },
    { "regswap1",       REG_XY,               REG_A                          },
    { "regswap2",       REG_XY,               REG_A | REG_Y                  },
    { "return0",        REG_NONE,             REG_AX                         },
    { "return1",        REG_NONE,             REG_AX                         },
    { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
    { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
    { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
    { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
    { "shlaxy",         REG_AXY,              REG_AXY | REG_TMP1             },
    { "shleax1",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shleax2",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shleax3",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shleax4",        REG_EAX,              REG_EAXY | REG_TMP1            },
    { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
    { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
    { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
    { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
    { "shraxy",         REG_AXY,              REG_AXY | REG_TMP1             },
    { "shreax1",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shreax2",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shreax3",        REG_EAX,              REG_EAX | REG_TMP1             },
    { "shreax4",        REG_EAX,              REG_EAXY | REG_TMP1            },
    { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
    { "stax0sp",        REG_AX,               REG_Y                          },
    { "staxspidx",      REG_AXY,              REG_TMP1 | REG_PTR1            },
    { "staxysp",        REG_AXY,              REG_Y                          },
    { "steax0sp",       REG_EAX,              REG_Y                          },
    { "steaxysp",       REG_EAXY,             REG_Y                          },
    { "subeq0sp",       REG_AX,               REG_AXY                        },
    { "subeqysp",       REG_AXY,              REG_AXY                        },
    { "subysp",         REG_Y,                REG_AY                         },
    { "tosadd0ax",      REG_AX,               REG_EAXY | REG_TMP1            },
    { "tosadda0",       REG_A,                REG_AXY                        },
    { "tosaddax",       REG_AX,               REG_AXY                        },
    { "tosaddeax",      REG_EAX,              REG_EAXY | REG_TMP1            },
    { "tosand0ax",      REG_AX,               REG_EAXY | REG_TMP1            },
    { "tosanda0",       REG_A,                REG_AXY                        },
    { "tosandax",       REG_AX,               REG_AXY                        },
    { "tosandeax",      REG_EAX,              REG_EAXY | REG_TMP1            },
    { "tosaslax",       REG_A,                REG_AXY | REG_TMP1             },
    { "tosasleax",      REG_A,                REG_EAXY | REG_TMP1            },
    { "tosasrax",       REG_A,                REG_AXY | REG_TMP1             },
    { "tosasreax",      REG_A,                REG_EAXY | REG_TMP1            },
    { "tosdiv0ax",      REG_AX,               REG_ALL                        },
    { "tosdiva0",       REG_A,                REG_ALL                        },
    { "tosdivax",       REG_AX,               REG_ALL                        },
    { "tosdiveax",      REG_EAX,              REG_ALL                        },
    { "toseq00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "toseqa0",        REG_A,                REG_AXY | REG_SREG             },
    { "toseqax",        REG_AX,               REG_AXY | REG_SREG             },
    { "toseqeax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosge00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "tosgea0",        REG_A,                REG_AXY | REG_SREG             },
    { "tosgeax",        REG_AX,               REG_AXY | REG_SREG             },
    { "tosgeeax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosgt00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "tosgta0",        REG_A,                REG_AXY | REG_SREG             },
    { "tosgtax",        REG_AX,               REG_AXY | REG_SREG             },
    { "tosgteax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
    { "tosicmp0",       REG_A,                REG_AXY | REG_SREG             },
    { "toslcmp",        REG_EAX,              REG_A | REG_Y | REG_PTR1       },
    { "tosle00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "toslea0",        REG_A,                REG_AXY | REG_SREG             },
    { "tosleax",        REG_AX,               REG_AXY | REG_SREG             },
    { "tosleeax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "toslt00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "toslta0",        REG_A,                REG_AXY | REG_SREG             },
    { "tosltax",        REG_AX,               REG_AXY | REG_SREG             },
    { "toslteax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosmod0ax",      REG_AX,               REG_ALL                        },
    { "tosmodeax",      REG_EAX,              REG_ALL                        },
    { "tosmul0ax",      REG_AX,               REG_ALL                        },
    { "tosmula0",       REG_A,                REG_ALL                        },
    { "tosmulax",       REG_AX,               REG_ALL                        },
    { "tosmuleax",      REG_EAX,              REG_ALL                        },
    { "tosne00",        REG_NONE,             REG_AXY | REG_SREG             },
    { "tosnea0",        REG_A,                REG_AXY | REG_SREG             },
    { "tosneax",        REG_AX,               REG_AXY | REG_SREG             },
    { "tosneeax",       REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosor0ax",       REG_AX,               REG_EAXY | REG_TMP1            },
    { "tosora0",        REG_A,                REG_AXY | REG_TMP1             },
    { "tosorax",        REG_AX,               REG_AXY | REG_TMP1             },
    { "tosoreax",       REG_EAX,              REG_EAXY | REG_TMP1            },
    { "tosrsub0ax",     REG_AX,               REG_EAXY | REG_TMP1            },
    { "tosrsuba0",      REG_A,                REG_AXY | REG_TMP1             },
    { "tosrsubax",      REG_AX,               REG_AXY | REG_TMP1             },
    { "tosrsubeax",     REG_EAX,              REG_EAXY | REG_TMP1            },
    { "tosshlax",       REG_A,                REG_AXY | REG_TMP1             },
    { "tosshleax",      REG_A,                REG_EAXY | REG_TMP1            },
    { "tosshrax",       REG_A,                REG_AXY | REG_TMP1             },
    { "tosshreax",      REG_A,                REG_EAXY | REG_TMP1            },
    { "tossub0ax",      REG_AX,               REG_EAXY                       },
    { "tossuba0",       REG_A,                REG_AXY                        },
    { "tossubax",       REG_AX,               REG_AXY                        },
    { "tossubeax",      REG_EAX,              REG_EAXY                       },
    { "tosudiv0ax",     REG_AX,               REG_ALL & ~REG_SAVE            },
    { "tosudiva0",      REG_A,                REG_EAXY | REG_PTR1            }, /* also ptr4 */
    { "tosudivax",      REG_AX,               REG_EAXY | REG_PTR1            }, /* also ptr4 */
    { "tosudiveax",     REG_EAX,              REG_ALL & ~REG_SAVE            },
    { "tosuge00",       REG_NONE,             REG_AXY | REG_SREG             },
    { "tosugea0",       REG_A,                REG_AXY | REG_SREG             },
    { "tosugeax",       REG_AX,               REG_AXY | REG_SREG             },
    { "tosugeeax",      REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosugt00",       REG_NONE,             REG_AXY | REG_SREG             },
    { "tosugta0",       REG_A,                REG_AXY | REG_SREG             },
    { "tosugtax",       REG_AX,               REG_AXY | REG_SREG             },
    { "tosugteax",      REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosule00",       REG_NONE,             REG_AXY | REG_SREG             },
    { "tosulea0",       REG_A,                REG_AXY | REG_SREG             },
    { "tosuleax",       REG_AX,               REG_AXY | REG_SREG             },
    { "tosuleeax",      REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosult00",       REG_NONE,             REG_AXY | REG_SREG             },
    { "tosulta0",       REG_A,                REG_AXY | REG_SREG             },
    { "tosultax",       REG_AX,               REG_AXY | REG_SREG             },
    { "tosulteax",      REG_EAX,              REG_AXY | REG_PTR1             },
    { "tosumod0ax",     REG_AX,               REG_ALL & ~REG_SAVE            },
    { "tosumoda0",      REG_A,                REG_EAXY | REG_PTR1            }, /* also ptr4 */
    { "tosumodax",      REG_AX,               REG_EAXY | REG_PTR1            }, /* also ptr4 */
    { "tosumodeax",     REG_EAX,              REG_ALL & ~REG_SAVE            },
    { "tosumul0ax",     REG_AX,               REG_ALL                        },
    { "tosumula0",      REG_A,                REG_ALL                        },
    { "tosumulax",      REG_AX,               REG_ALL                        },
    { "tosumuleax",     REG_EAX,              REG_ALL                        },
    { "tosxor0ax",      REG_AX,               REG_EAXY | REG_TMP1            },
    { "tosxora0",       REG_A,                REG_AXY | REG_TMP1             },
    { "tosxorax",       REG_AX,               REG_AXY | REG_TMP1             },
    { "tosxoreax",      REG_EAX,              REG_EAXY | REG_TMP1            },
    { "tsteax",         REG_EAX,              REG_Y                          },
    { "utsteax",        REG_EAX,              REG_Y                          },
};
#define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))

/* Table with names of zero page locations used by the compiler */
static const ZPInfo ZPInfoTable[] = {
    {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
    {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
    {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
    {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
    {   4, "ptr3",      REG_NONE,       REG_NONE        },
    {   4, "ptr4",      REG_NONE,       REG_NONE        },
    {   7, "regbank",   REG_NONE,       REG_NONE        },
    {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
    {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
    {   0, "sp",        REG_SP_LO,      REG_SP          },
    {   0, "sp+1",      REG_SP_HI,      REG_SP          },
    {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
    {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
    {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
    {   0, "tmp2",      REG_NONE,       REG_NONE        },
    {   0, "tmp3",      REG_NONE,       REG_NONE        },
    {   0, "tmp4",      REG_NONE,       REG_NONE        },
};
#define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))



/*****************************************************************************/
/*                                   Code                                    */
/*****************************************************************************/



static int CompareFuncInfo (const void* Key, const void* Info)
/* Compare function for bsearch */
{
    return strcmp (Key, ((const FuncInfo*) Info)->Name);
}



void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
/* For the given function, lookup register information and store it into
 * the given variables. If the function is unknown, assume it will use and
 * load all registers.
 */
{
    /* If the function name starts with an underline, it is an external
     * function. Search for it in the symbol table. If the function does
     * not start with an underline, it may be a runtime support function.
     * Search for it in the list of builtin functions.
     */
    if (Name[0] == '_') {

        /* Search in the symbol table, skip the leading underscore */
        SymEntry* E = FindGlobalSym (Name+1);

        /* Did we find it in the top level table? */
        if (E && IsTypeFunc (E->Type)) {

            FuncDesc* D = E->V.F.Func;

            /* A function may use the A or A/X registers if it is a fastcall
             * function. If it is not a fastcall function but a variadic one,
             * it will use the Y register (the parameter size is passed here).
             * In all other cases, no registers are used. However, we assume
             * that any function will destroy all registers.
             */
            if (IsQualFastcall (E->Type) && D->ParamCount > 0) {
                /* Will use registers depending on the last param */
                unsigned LastParamSize = CheckedSizeOf (D->LastParam->Type);
                if (LastParamSize == 1) {
                    *Use = REG_A;
                } else if (LastParamSize == 2) {
                    *Use = REG_AX;
                } else {
                    *Use = REG_EAX;
                }
            } else if ((D->Flags & FD_VARIADIC) != 0) {
                *Use = REG_Y;
            } else {
                /* Will not use any registers */
                *Use = REG_NONE;
            }

            /* Will destroy all registers */
            *Chg = REG_ALL;

            /* Done */
            return;
        }

    } else if (IsDigit (Name[0]) || Name[0] == '$') {

        /* A call to a numeric address. Assume that anything gets used and
         * destroyed. This is not a real problem, since numeric addresses
         * are used mostly in inline assembly anyway.
         */
        *Use = REG_ALL;
        *Chg = REG_ALL;
        return;

    } else {

        /* Search for the function in the list of builtin functions */
        const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
                                        sizeof(FuncInfo), CompareFuncInfo);

        /* Do we know the function? */
        if (Info) {
            /* Use the information we have */
            *Use = Info->Use;
            *Chg = Info->Chg;
        } else {
            /* It's an internal function we have no information for. If in
             * debug mode, output an additional warning, so we have a chance
             * to fix it. Otherwise assume that the internal function will
             * use and change all registers.
             */
            if (Debug) {
                fprintf (stderr, "No info about internal function `%s'\n", Name);
            }
            *Use = REG_ALL;
            *Chg = REG_ALL;
        }
        return;
    }

    /* Function not found - assume that the primary register is input, and all
     * registers are changed
     */
    *Use = REG_EAXY;
    *Chg = REG_ALL;
}



static int CompareZPInfo (const void* Name, const void* Info)
/* Compare function for bsearch */
{
    /* Cast the pointers to the correct data type */
    const char* N   = (const char*) Name;
    const ZPInfo* E = (const ZPInfo*) Info;

    /* Do the compare. Be careful because of the length (Info may contain
     * more than just the zeropage name).
     */
    if (E->Len == 0) {
        /* Do a full compare */
        return strcmp (N, E->Name);
    } else {
        /* Only compare the first part */
        int Res = strncmp (N, E->Name, E->Len);
        if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
            /* Name is actually longer than Info->Name */
            Res = -1;
        }
        return Res;
    }
}



const ZPInfo* GetZPInfo (const char* Name)
/* If the given name is a zero page symbol, return a pointer to the info
 * struct for this symbol, otherwise return NULL.
 */
{
    /* Search for the zp location in the list */
    return bsearch (Name, ZPInfoTable, ZPInfoCount,
                    sizeof(ZPInfo), CompareZPInfo);
}



static unsigned GetRegInfo2 (CodeSeg* S,
                             CodeEntry* E,
                             int Index,
                             Collection* Visited,
                             unsigned Used,
                             unsigned Unused,
                             unsigned Wanted)
/* Recursively called subfunction for GetRegInfo. */
{
    /* Follow the instruction flow recording register usage. */
    while (1) {

        unsigned R;

        /* Check if we have already visited the current code entry. If so,
         * bail out.
         */
        if (CE_HasMark (E)) {
            break;
        }

        /* Mark this entry as already visited */
        CE_SetMark (E);
        CollAppend (Visited, E);

        /* Evaluate the used registers */
        R = E->Use;
        if (E->OPC == OP65_RTS ||
            ((E->Info & OF_UBRA) != 0 && E->JumpTo == 0)) {
            /* This instruction will leave the function */
            R |= S->ExitRegs;
        }
        if (R != REG_NONE) {
            /* We are not interested in the use of any register that has been
             * used before.
             */
            R &= ~Unused;
            /* Remember the remaining registers */
            Used |= R;
        }

        /* Evaluate the changed registers */
        if ((R = E->Chg) != REG_NONE) {
            /* We are not interested in the use of any register that has been
             * used before.
             */
            R &= ~Used;
            /* Remember the remaining registers */
            Unused |= R;
        }

        /* If we know about all registers now, bail out */
        if (((Used | Unused) & Wanted) == Wanted) {
            break;
        }

        /* If the instruction is an RTS or RTI, we're done */
        if ((E->Info & OF_RET) != 0) {
            break;
        }

        /* If we have an unconditional branch, follow this branch if possible,
         * otherwise we're done.
         */
        if ((E->Info & OF_UBRA) != 0) {

            /* Does this jump have a valid target? */
            if (E->JumpTo) {

                /* Unconditional jump */
                E     = E->JumpTo->Owner;
                Index = -1;             /* Invalidate */

            } else {
                /* Jump outside means we're done */
                break;
            }

        /* In case of conditional branches, follow the branch if possible and
         * follow the normal flow (branch not taken) afterwards. If we cannot
         * follow the branch, we're done.
         */
        } else if ((E->Info & OF_CBRA) != 0) {

            /* Recursively determine register usage at the branch target */
            unsigned U1;
            unsigned U2;

            if (E->JumpTo) {

                /* Jump to internal label */
                U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);

            } else {

                /* Jump to external label. This will effectively exit the
                 * function, so we use the exitregs information here.
                 */
                U1 = S->ExitRegs;

            }

            /* Get the next entry */
            if (Index < 0) {
                Index = CS_GetEntryIndex (S, E);
            }
            if ((E = CS_GetEntry (S, ++Index)) == 0) {
                Internal ("GetRegInfo2: No next entry!");
            }

            /* Follow flow if branch not taken */
            U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);

            /* Registers are used if they're use in any of the branches */
            return U1 | U2;

        } else {

            /* Just go to the next instruction */
            if (Index < 0) {
                Index = CS_GetEntryIndex (S, E);
            }
            E = CS_GetEntry (S, ++Index);
            if (E == 0) {
                /* No next entry */
                Internal ("GetRegInfo2: No next entry!");
            }

        }

    }

    /* Return to the caller the complement of all unused registers */
    return Used;
}



static unsigned GetRegInfo1 (CodeSeg* S,
                             CodeEntry* E,
                             int Index,
                             Collection* Visited,
                             unsigned Used,
                             unsigned Unused,
                             unsigned Wanted)
/* Recursively called subfunction for GetRegInfo. */
{
    /* Remember the current count of the line collection */
    unsigned Count = CollCount (Visited);

    /* Call the worker routine */
    unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);

    /* Restore the old count, unmarking all new entries */
    unsigned NewCount = CollCount (Visited);
    while (NewCount-- > Count) {
        CodeEntry* E = CollAt (Visited, NewCount);
        CE_ResetMark (E);
        CollDelete (Visited, NewCount);
    }

    /* Return the registers used */
    return R;
}



unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
/* Determine register usage information for the instructions starting at the
 * given index.
 */
{
    CodeEntry*      E;
    Collection      Visited;    /* Visited entries */
    unsigned        R;

    /* Get the code entry for the given index */
    if (Index >= CS_GetEntryCount (S)) {
        /* There is no such code entry */
        return REG_NONE;
    }
    E = CS_GetEntry (S, Index);

    /* Initialize the data structure used to collection information */
    InitCollection (&Visited);

    /* Call the recursive subfunction */
    R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);

    /* Delete the line collection */
    DoneCollection (&Visited);

    /* Return the registers used */
    return R;
}



int RegAUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in A is used. */
{
    return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
}



int RegXUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in X is used. */
{
    return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
}



int RegYUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in Y is used. */
{
    return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
}



int RegAXUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in A or(!) the value in X are used. */
{
    return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
}



int RegEAXUsed (struct CodeSeg* S, unsigned Index)
/* Check if any of the four bytes in EAX are used. */
{
    return (GetRegInfo (S, Index, REG_EAX) & REG_EAX) != 0;
}



unsigned GetKnownReg (unsigned Use, const RegContents* RC)
/* Return the register or zero page location from the set in Use, thats
 * contents are known. If Use does not contain any register, or if the
 * register in question does not have a known value, return REG_NONE.
 */
{
    if ((Use & REG_A) != 0) {
        return (RC == 0 || RC->RegA >= 0)? REG_A : REG_NONE;
    } else if ((Use & REG_X) != 0) {
        return (RC == 0 || RC->RegX >= 0)? REG_X : REG_NONE;
    } else if ((Use & REG_Y) != 0) {
        return (RC == 0 || RC->RegY >= 0)? REG_Y : REG_NONE;
    } else if ((Use & REG_TMP1) != 0) {
        return (RC == 0 || RC->Tmp1 >= 0)? REG_TMP1 : REG_NONE;
    } else if ((Use & REG_PTR1_LO) != 0) {
        return (RC == 0 || RC->Ptr1Lo >= 0)? REG_PTR1_LO : REG_NONE;
    } else if ((Use & REG_PTR1_HI) != 0) {
        return (RC == 0 || RC->Ptr1Hi >= 0)? REG_PTR1_HI : REG_NONE;
    } else if ((Use & REG_SREG_LO) != 0) {
        return (RC == 0 || RC->SRegLo >= 0)? REG_SREG_LO : REG_NONE;
    } else if ((Use & REG_SREG_HI) != 0) {
        return (RC == 0 || RC->SRegHi >= 0)? REG_SREG_HI : REG_NONE;
    } else {
        return REG_NONE;
    }
}



static cmp_t FindCmpCond (const char* Code, unsigned CodeLen)
/* Search for a compare condition by the given code using the given length */
{
    unsigned I;

    /* Linear search */
    for (I = 0; I < sizeof (CmpSuffixTab) / sizeof (CmpSuffixTab [0]); ++I) {
        if (strncmp (Code, CmpSuffixTab [I], CodeLen) == 0) {
            /* Found */
            return I;
        }
    }

    /* Not found */
    return CMP_INV;
}



cmp_t FindBoolCmpCond (const char* Name)
/* Check if the given string is the name of one of the boolean transformer
 * subroutine, and if so, return the condition that is evaluated by this
 * routine. Return CMP_INV if the condition is not recognised.
 */
{
    /* Check for the correct subroutine name */
    if (strncmp (Name, "bool", 4) == 0) {
        /* Name is ok, search for the code in the table */
        return FindCmpCond (Name+4, strlen(Name)-4);
    } else {
        /* Not found */
        return CMP_INV;
    }
}



cmp_t FindTosCmpCond (const char* Name)
/* Check if this is a call to one of the TOS compare functions (tosgtax).
 * Return the condition code or CMP_INV on failure.
 */
{
    unsigned Len = strlen (Name);

    /* Check for the correct subroutine name */
    if (strncmp (Name, "tos", 3) == 0 && strcmp (Name+Len-2, "ax") == 0) {
        /* Name is ok, search for the code in the table */
        return FindCmpCond (Name+3, Len-3-2);
    } else {
        /* Not found */
        return CMP_INV;
    }
}



