| [hatari-devel] Reeking rumber analysis |
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Hi,
I've given a closer look at reeking rumber :
I can let it run under hatari by doing the following :
Under the GEM :
b pc=$0707d8
Then, start reeking rumbler by double clicking it
hen the breakpoint is reached, just do
r d5=0
c
and the game run
Here is the corresponding code:
The part of the code that calls the faulty function :
$06f942 : 207c 0009 3850 movea.l #$93850,a0
$06f948 : 4240 clr.w d0
$06f94a : 323c 0100 move.w #$100,d1
$06f94e : 7401 moveq #1,d2
$06f950 : 6100 0dd6 bsr $70728
The part of the code that loops forever :
$070728 : 48e7 ffe0 movem.l d0-d7/a0-a2,-(sp)
$07072c : 4a41 tst.w d1
$07072e : 6700 00ac beq $707dc
$070732 : 48e7 e080 movem.l d0-d2/a0,-(sp)
>
$070736 : 3f3c 0025 move.w #$25,-(sp)
$07073a : 4e4e trap #$e
$07073c : 544f addq.w #2,sp
$07073e : 4cdf 0107 movem.l (sp)+,d0-d2/a0
$070742 : 43f8 9800 lea $ffff9800.w,a1
$070746 : 3e00 move.w d0,d7
$070748 : e54f lsl.w #2,d7
$07074a : d2c7 adda.w d7,a1
>
$07074c : 45f9 0008 d8f0 lea $8d8f0,a2
$070752 : 3601 move.w d1,d3
$070754 : 5343 subq.w #1,d3
$070756 : 24d9 move.l (a1)+,(a2)+
$070758 : 51cb fffc dbra d3,$70756
$07075c : 7a00 moveq #0,d5
$07075e : 48e7 e080 movem.l d0-d2/a0,-(sp)
$070762 : 3802 move.w d2,d4
>
$070764 : 3f3c 0025 move.w #$25,-(sp)
$070768 : 4e4e trap #$e
$07076a : 544f addq.w #2,sp
$07076c : 51cc fff6 dbra d4,$70764
$070770 : 4cdf 0107 movem.l (sp)+,d0-d2/a0
$070774 : 43f9 0008 d8f0 lea $8d8f0,a1
$07077a : 45f8 9800 lea $ffff9800.w,a2
$07077e : 3e00 move.w d0,d7
>
$070780 : e54f lsl.w #2,d7
$070782 : d4c7 adda.w d7,a2
$070784 : 3601 move.w d1,d3
$070786 : 5343 subq.w #1,d3
$070788 : 24d9 move.l (a1)+,(a2)+
$07078a : 51cb fffc dbra d3,$70788
$07078e : 45f9 0008 d8f0 lea $8d8f0,a2
$070794 : 2248 movea.l a0,a1
>
$070796 : 3e00 move.w d0,d7
$070798 : e54f lsl.w #2,d7
$07079a : d2c7 adda.w d7,a1
$07079c : 3c01 move.w d1,d6
$07079e : 5346 subq.w #1,d6
$0707a0 : 2811 move.l (a1),d4
$0707a2 : 2612 move.l (a2),d3
$0707a4 : b803 cmp.b d3,d4
>
$0707a6 : 6706 beq.s $707ae
$0707a8 : 6202 bhi.s $707ac
$0707aa : 5103 subq.b #8,d3
$0707ac : 5803 addq.b #4,d3
$0707ae : e19b rol.l #8,d3
$0707b0 : e19c rol.l #8,d4
$0707b2 : b803 cmp.b d3,d4
$0707b4 : 6706 beq.s $707bc
>
$0707b6 : 6202 bhi.s $707ba
$0707b8 : 5103 subq.b #8,d3
$0707ba : 5803 addq.b #4,d3
$0707bc : e19b rol.l #8,d3
$0707be : e19c rol.l #8,d4
$0707c0 : b803 cmp.b d3,d4
$0707c2 : 6706 beq.s $707ca
$0707c4 : 6202 bhi.s $707c8
>
$0707c6 : 5103 subq.b #8,d3
$0707c8 : 5803 addq.b #4,d3
$0707ca : 4843 swap d3
$0707cc : b699 cmp.l (a1)+,d3
$0707ce : 6702 beq.s $707d2
$0707d0 : 7a01 moveq #1,d5
$0707d2 : 24c3 move.l d3,(a2)+
$0707d4 : 51ce ffca dbra d6,$707a0
>
$0707d8 : 4a85 tst.l d5
<------- Here is the the test that never goes throw with hatari
$0707da : 6680 bne.s $7075c
$0707dc : 4cdf 07ff movem.l (sp)+,d0-d7/a0-a2
$0707e0 : 4e75 rts
At least, the game runs under hatari except for this infinite loop that
never finishs because of this d5 register.
May this gives some ideas to somebody.
Regards
Laurent