Looks like it's a conflict between the two implementations of the rand function.

When the include file is not used, it uses the rand function that calls the ROM, when the include file is used, it calls the

rand32() through a macro which makes no sense to me, either I was drunk or I was tired:

#define rand() (

rand32()?(randseedTop & 0x7fff):(randseedTop & 0x7fff))

So one one side we have:

rand.s

Code: Select all

```
_rand
_random
ldx #$ff
jsr $E355
ldx $D2
lda $D1
rts
_srandom
ldy #0
lda (sp),y
sta $FC
sta $FE
iny
lda (sp),y
sta $FB
sta $FD
lda #$80
sta $FA
rts
```

and on the other:

random.s

Code: Select all

```
;
; int random(void) ; return a random value in 0..32767
;
_rand
_random
;
; int srandom(int seed) ; initialize the random generator
;
_srandom
```

which suspiciously looks like some stuff is missing...

but we find that in mult32:

Code: Select all

```
/*
int rand(void)
{
return( ((_holdrand = _holdrand * 214013L + 2531011L) >> 16) & 0x7fff );
}
*/
_randseedLow .byt 0,0
_randseedTop .byt 0,0
_rand32
;jmp _pcrand
.(
; Left side, old seed
lda _randseedLow+0
sta tmp0+0
lda _randseedLow+1
sta tmp0+1
lda _randseedLow+2
sta tmp0+2
lda _randseedLow+3
sta tmp0+3
; Righ side, 214013 -> $00 03 43 FD
lda #$FD
sta tmp2+0
lda #$43
sta tmp2+1
lda #$03
sta tmp2+2
lda #$00
sta tmp2+3
; Multiply
; Result in tmp4/5/6/6/7
jsr mul32u
; Add 2531011 -> $00 26 9E C3
clc
lda tmp4+0
adc #$C3
sta _randseedLow+0
lda tmp4+1
adc #$9E
sta _randseedLow+1
lda tmp4+2
adc #$26
sta _randseedLow+2
lda tmp4+3
adc #$00
sta _randseedLow+3
rts
.)
```

To me it looks like some unfinished stuff that I probably forgot when I was working on FreeCell: My game needed a random generator which worked *exactly* like the one used on the Windows version, so this

rand32 is the real deal.

Now, why the 32bit version of rand corrupts your variables... I don't know...

Try to comment the #define rand() in lib.h, see if that solve the issue.