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%% 68060 Upgrade Software Guide                      By: Ralph Schmidt  %%
%% Tips and tricks for speedsters...            laire@uni-paderborn.de  %%
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0) Advanced System & Software will sell the first 060 accelerator,
   namely the Cyberstorm 060, rather soon and wants to achieve a smooth
   integration into the Amiga.
   Therefore we hope that software companys and pd programmers
   will adopt their software to deal with the 68060.

1) Inststructions supported by the 68040 but not by the 68060 directly that
   can hurt performance:

 o divx.l (64bit divide)
 o mulx.l (64bit multiply)
 o fdbcc
 o fscc
 o movep
 o There are other instructions that are not supported or have to
   be emulated but these aren't relevant for user applications.

2) Instructions supported by the 68060 in hardware that are emulated on
   the 68040:

 o fint
 o fintrz

3) Emulation limitations

The emulation can't reliably emulate unsupported instructions
that access the (ssp) in a way that it contradicts the basic
definition of a stack. (ssp)=sp in supervisor mode.
I don't think anybody is using such constructs in his software
but I want to mention it to stop anybody from using these:

div{u,s}.l              -(ssp),dr:dq
mul{u,s}.l              -(ssp),dr:dq
f.p                 -(ssp),fpn
f.p                 fpn,(ssp)+
f.{b,w,l,s,d,x}     -(ssp),fpn
fs.b                -(ssp)
fmovem.x                -(ssp),dn
fmovem.x                dn,(ssp)+
f.x                 fpn,(ssp)+      ;Underflow,SNAN exception
f.{b,w,l}           fpn,(ssp)+      ;Enabled OPERR



4) Other software problems.

  o Don't use Aztec C.
    It is not compatible with the 68060.
    Popular applications with this problem: CED 2.02,CED 3.5,Mand2000D
    *I fixed this by patching Supervisor()*,
    so don't worry about your programs but
    don't use it in future software if possible.

    Here's the bad Code:

        btst.b  #4,$129(a6)             ;check for 68881 flag in AttnFlags
        beq     1$                      ;skip if not
        lea     2$,a5
        jsr     -30(a6)                 ;do it in supervisor mode
        bra     1$
    2$
        clr.l   -(sp)
        frestore (sp)+                  ;reset the ffp stuff
    ;The 68060 FRestore stackframe is 12 bytes long but it only created
    ;a NULL frame with the size of 4 Bytes so the Stack is wrong afterwards.
    ;RTE->jump into unknown regions...crash
        rte                             ;and return

5) New Stackframe format

   These informations are only interesting for Debugger programmers
   and kernel hackers.

   o 3-Byte in the 1st Longword = 0 then NULL Stackframe.
     xxxx00xx   ;1st Longword of the FPU stackframe
     xxxxxxxx   ;2nd Longword of the FPU stackframe
     xxxxxxxx   ;3rd Longword of the FPU stackframe
     xxxxxxxx   ;PC
     xxxx       ;SR
     d0-a6      ;Registers


   o 3-Byte in the 1st Longword !=0 then BUSY Stackframe.
     ffffffff   ;Busy Fake Longword
     xxxxxxxx   ;FPCR
     xxxxxxxx   ;FPSR
     xxxxxxxx   ;FPIAR
     fp0-fp7    ;FPU Registers
     xxxxxxxx   ;1st Longword of the FPU stackframe
     xxxxxxxx   ;2nd Longword of the FPU stackframe
     xxxxxxxx   ;3rd Longword of the FPU stackframe
     xxxxxxxx   ;PC
     xxxx       ;SR
     d0-a6      ;Registers


6) MMU Table differences

   The 68040 and 68060 mmu tables are almost the same but there is
   an important difference. For the 68060 the MMU-Tables have to
   be placed into non-cached ram!!!!!!!
   So if you manipulate the mmu-table you have to mark the pages
   with your added tables as non-cacheable.
   Another difference is that the Cyberstorm software uses the
   area $ffff8000-$ffffffff for itself.
   You are NOT allowed to change the mmu-table that this area
   is touched in any way. This can lead to serious crashes.


7) Barfly 1.09 is the first Assembler/Debugger that supports the
   68060. It can be found on aminet:dev/asm/barfly1_09.lha