BF Compiler

#include <stdio.h>
#include <stack>

int main(){
    //Initialise the butters
    std::stack<int> s;         //Stack to hold '[' locations
    char in[100000];           //input butter
    printf( ": "); gets( in ); //Get the BF program
    FILE* a = fopen( "out.bin", "w" );
    int p = 0x9D93; //This is the Texas Instruments magic number for where programs are loaded in memory

    fprintf( a, "%c%c", 0xBB, 0x6D ); p+=2;     //.DB BBh,6Dh       ;Declare an ASM program
    char getAnstoDE[] = {   0x21, 0x78, 0x84,   //LD HL,OP1         ;Spell out the Ans variable
                            0x36, 0x04,         //LD (HL),StrngObj  ;...
                            0x23,               //INC HL            ;...
                            0x36, 0x72,         //LD (HL),tAns      ;...
                            0x23,               //INC HL            ;...
                            0x36, 0x00,         //LD (HL),0         ;...
                            0x23,               //INC HL            ;...
                            0x36, 0x00,         //LD (HL),0         ;...
                            0xEF, 0xF4, 0x42,   //B_CALL(_FindSym)  ;Load the pointer to a string in to DE
                            0x1A, 0x6f,         //LD L,(DE)         ;Get the strings length in to HL
                            0x13,               //INC DE            ;...
                            0x1A, 0x67,         //LD H,(DE)         ;...
                            0x13,               //INC DE            ;...
                            0x19,               //ADD HL,DE         ;Move HL to the end of the string
                            0x36, 0x00          //LD (HL),0         ;Null-terminate it
                            };
    fwrite( getAnstoDE, 26, 1, a ); p += 26;
    fprintf( a, "%c%c%c", 0x21, 0xEC, 0x86 ); p+=3; //LD HL,86ECh   ;Safe RAM

    fprintf( a, "%c%c", 0x3E, 0xFF ); p+=2;         //LD A,FFh      ;Set the counter to 0xFF
    fprintf( a, "%c%c%c%c%c%c%c%c%c",
            0x36, 0,                    //LD (HL),0         ;Clear the next 256 bytes
            0x23,                       //INC HL            ;...
            0x3D,                       //DEC A             ;...
            0xFE, 0,                    //CP 0              ;...
            0xC2, p&0xFF,(p>>8)&0xFF ); //JP NZ,(BEGINLOOP) ;...
            p+=9;
    fprintf( a, "%c%c%c%c%c",
            0x21, 0xEC, 0x86,           //LD HL,86ECh       ;Jump back to the start of the safe RAM
            0x06, 0x00 ); p+=5;         //LD B,0            ;Set the bounds checker to 0

    for( int i = 0; in[i] != 0; i ++ ){
        switch( in[i] ){
            case '+':
                fprintf( a, "%c", 0x34 ); p++;      //INC (HL)
                break;
            case '-':
                fprintf( a, "%c", 0x35 ); p++;      //DEC (HL)
                break;
            case '>':
                fprintf( a, "%c%c%c%c%c%c%c%c%c",
                    0x23,       //INC HL    ;Move the pointer forwards
                    0x78,       //LD A,B    ;Move the Bounds Checker to the Accumulator
                    0xC6, 0x01, //ADD A,1   ;Increase the bounds checker
                    0x30,0x01,  //JR NC,1   ;If there was an overflow, then move the pointer back by 256
                    0x25,       //DEC H     ;...
                    0x47 );p+=8;//LD B,A    ;Move the Accumulator to the Bounds Checker
                break;
            case '<':
                fprintf( a, "%c%c%c%c%c%c%c%c%c",
                0x2B,       //DEC HL    ;Move the pointer backwards
                0x78,       //LD A,B    ;Move the Bounds Checker to the Accumulator
                0xD6, 0x01, //SUB A,1   ;Decrease the bounds checker
                0x30, 0x01, //JR NC,1   ;If there was an overflow, then move the pointer forward by 256
                0x24,       //INC H     ;...
                0x47 );p+=8;//LD B,A    ;Move the Accumulator to the Bounds Checker
                break;
            case '[':
            {
                s.push( p+6 );  //Track the location of this for jumping back
                int pp = p;     //Temp pointer
                for( int j = i+1, depth = 1; in[j] != 0; j++ ){     //Find the matching ']'
                    if( in[j] == '[' ) depth ++;
                    if( in[j] == ']' ) depth --;
                    if( in[j] == '+' || in[j] == '-' ){
                        pp++;
                    }
                    if( in[j] == '<' || in[j] == '>' ){
                        pp+=8;
                    }

                    if( in[j] == '[' || in[j] == ']' ){
                        pp+=6;
                    }
                    if( in[j] == '.'){
                        pp+=4;
                    }
                    if( in[j] == ','){
                        pp+=7;
                    }

                    if( depth <= 0 ) break;
                }
                fprintf( a, "%c%c%c%c%c%c",
                        0x7E,                       //LD A,(HL)         ;Grab the byte at the pointer and jump to the matching ']' if zero
                        0xFE, 0x00,                 //CP 0              ;...
                        0xCA, pp&0xFF, (pp>>8)&0xFF //JP Z,(MATCHING ]) ;...
                         ); p+=6;
            } break;
            case ']':
            {
                int pp = s.top( );
                s.pop();
                fprintf( a, "%c%c%c%c%c%c",
                        0x7E,                       //LD A,(HL)             ;Grab the byte at the pointer and jump to the matching '[' if not zero
                        0xFE, 0x00,                 //CP 0                  ;...
                        0xC2, pp&0xFF, (pp>>8)&0xFF //JP NZ,(MATCHING [)    ;...
                        ); p+=6;
            } break;
            case '.':
            {
                fprintf( a, "%c%c%c%c",
                        0x7E,               //LD A,(HL)     ;Print the character being pointed at
                        0xEF, 0x04, 0x45    //B_CALL(PutC)  ;...
                        ); p+=4;
            } break;
            case ',':
            {
                fprintf( a, "%c%c%c%c%c%c%c",
                        0x1A,       //LD A,(DE) ;Get the next char on the input stream
                        0x77,       //LD (HL),A ;Stick it in to the memory at pointer
                        0xFE, 0x00, //CP 0      ;If it's zero, then don't increase the input stream pointer
                        0x28, 0x01, //JR Z,1    ;...
                        0x13);p+=7; //INC DE    ;...
            } break;

        }
    }
    fprintf( a, "%c", 0xC9 ); p+=1; //RET   ;Return control to the TI-OS
}