lcc for the GS - info

[tm@netcom.com (Toshiyasu Morita)]

If anyone's interested, I've been working on an 65816 C compiler for a while
and it's starting to generate code.
 
Briefly, the C compiler consists of the lcc-1.9 C front-end and a custom
code generator back-end which outputs code for a 32-bit single register
virtual machine, and a utility called VM2GS which reads VM code and
outputs peephole-optimized 65816 code.
 
Currently it's hosted under MS-DOS (Watcom C/386), and there are no libraries
for it yet so it's not ready for general use, but it may be attractive for
hardcore programmers.
 
If you're a C/assembly programmer and would like to help by 
bug-hunting, writing libraries, or attempting to compile it 
under ORCA/C please send mail to me (tm@netcom.com).
 
 
 
For the curious, here's some sample input code:
 
char *strcat(char *s1, const char *s2)
 
{
        char *dest = s1;
 
        while (*dest)
                dest++;
 
        while (*dest++ = *s2++);
 
        return s1;
}
 
and the corresponding output: (comments and spacing mine)
 
_strcat	start
        longa   on
        longi   on
scratch equ     1
_dest   equ     5
temp0   equ     9
temp1   equ     11
temp2   equ     13
temp3   equ     15
_s1     equ     20
_s2     equ     24
        tsc
        sec
        sbc     #16
        tcs
        phd
        tcd
 
        lda     <_s1            ; *dest = *s1;
        ldx     <_s1+2
        sta     <_dest
        stx     <_dest+2
        jmp     L40
 
L39     anop
        inc     <_dest          ; dest++;
        bne     *+4
        inc     <_dest+2
 
L40     anop                    ; if (*dest != 0) goto L39
        lda     [<_dest]
        and     #$00ff
        ldx     #0
        bit     #$0080
        beq     *+6
        ora     #$ff00
        dex
        sta     scratch
        stx     scratch+2
        CMP4    scratch,#0
        beq     *+5
        jmp     L39
 
L42     anop
L43     anop                    ; temp0 = dest; dest++;
        lda     <_dest
        ldx     <_dest+2
        sta     <temp0
        stx     <temp0+2
        inc     a
        bne     *+3
        inx
        sta     <_dest
        stx     <_dest+2
 
        lda     <_s2            ; temp2 = s2; s2++;
        ldx     <_s2+2
        sta     <temp2
        stx     <temp2+2
        inc     a
        bne     *+3
        inx
        sta     <_s2
        stx     <_s2+2
 
        lda     [<temp2]        ; *temp0 = *temp2;
        sta     <temp2
        sep     #$20
        longa   off
        sta     <temp3
        rep     #$20
        longa   on
        lda     <temp3
        sep     #$20
        longa   off
        sta     [<temp0]
        rep     #$20
        longa   on
 
        lda     <temp2          ; if (*temp2 != 0) goto L42
        ldx     <temp2+2
        and     #$00ff
        ldx     #0
        bit     #$0080
        beq     *+6
        ora     #$ff00
        dex
        sta     scratch
        stx     scratch+2
        CMP4    scratch,#0
        beq     *+5
        jmp     L42
 
        lda     <_s1            ; return s1;
        ldx     <_s1+2
        tay
        pld
        tsc
        clc
        adc     #16
        tcs
        tya
        rtl
 
L38     anop                    ; (extra return code I haven't suppressed yet)
        tay
        pld
        tsc
        clc
        adc     #16
        tcs
        tya
        rtl
_strcat end          
 
 
Toshi Morita
tm@netcom.com