Wolin - a minimal Kotlin-like language compiler for 65xx

[qus]

Yep:

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__wolin_lab_loop_start_1:

; 12: add 53280[ubyte] = 53280[ubyte] , #1[ubyte] 


    inc 53280

; 13: evalless CPU.NC[bool] = 53280[ubyte] , #255[ubyte] 


    lda 53280
    cmp #255

; 14: bift CPU.NC[bool] , __wolin_lab_loop_start_1<while_start>[uword] 


	bcc __wolin_lab_loop_start_1

[BillG]

qus wrote:

; 13: evalless CPU.NC[bool] = 53280[ubyte] , #255[ubyte]

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    lda 53280
    cmp #255

If X or Y is available, you can compare a byte with 255 (or 1) with something like:

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    ldx    53280
    inx            ; (or dex)

    beq

[qus]

Heh, thanks. It will probably be good for 6502 asm optimization phase, though.

[dmsc]

Hi!

qus wrote:

Some compiler fun. I've compiled the same code with Wolin, cc65 and vbcc:

Wolin:

C (generated by Wolin C frontend )

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  do {
      (*(unsigned char *)(53280))++;
   } while ( (*(unsigned char *)(53280)) < 255);

cc65:

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L0015:	ldx     #$00
	lda     $D020
	inc     $D020
	ldx     #$00
	lda     $D020
	cmp     #$FF
	jsr     boolult
	jne     L0015

I wonder if I can make my bool operations any smarter and use V/C/N flags somehow (and obviously win brevity competition)... But I do like the way it works now - by storing the final bool result of an operation in SP reg. MAYBE instead of storing it at SP,x I just pretend I "stored" it at 6502 V/C/N?

You compiled the CC65 example without optimizations, here I get (using "cc65 -Osir test.c":

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L000B:  inc     $D020
        lda     $D020
        cmp     #$FF
        bcc     L000B

Have Fun!

[qus]

With such optimizations one has to wonder why are they turned off by default...

[Chromatix]

Most C compilers have no optimisation by default, so cc65 is not unusual in that respect. Unoptimised compilation results in code that does fewer unexpected things when single-stepping in a debugger.