Hi, this is just an EXPERIMENT. Words for flash XOR checksum (tested with 1284p). Each i! writes a XOR checksum of the whole flash(!) to the variable fxorsum. When after a crash something changes in flash the checkflash shall show non zero. Not easy to simulate (as you cannot use i!). The duration of fxor is 55ms at 25 MHz. Therefore let us call it an experiment.
; word fxor ( flashsize-1 -- xorsum) flash XOR sum ; R( -- ) ; Pito 21-9-2010 ; returns XOR checksum of flash VE_FXOR: .dw $ff04 .db "fxor" .dw VE_HEAD .set VE_HEAD = VE_FXOR XT_FXOR: .dw PFA_FXOR PFA_FXOR: movw zl, tosl ldi tosl, 0x00 ldi tosh, 0x00 loopfxor: movw R14, zl clr R18 lsl zl rol zh rol R18 out RAMPZ, R18 elpm R16, Z+ elpm R17, Z+ eor tosl, R16 eor tosh, R17 movw zl, R14 sbiw zl, 0x0001 sbiw zl, 0x0000 brne loopfxor jmp_ DO_NEXT \ i! with xorchecksum \ pito 21-9-2010 \ \ XOR sum of flash in forth : ffxor ( flashsize-1 -- ffxorsum ) 0 swap begin dup i@ rot xor swap 1- dup 0 = until drop ; variable fxorsum : ixorsum! (i!) $ffff fxor fxorsum ! ; ' ixorsum! is i! : checkflash $ffff fxor fxorsum @ - u. ; ******************************************************* Ex: > $ffff ffxor u. A3F9 ok > $ffff fxor u. A3F9 ok > fxorsum @ u. 6607 ok > variable hello ok > $ffff ffxor u. 55B3 ok > $ffff fxor u. 55B3 ok > fxorsum @ u. 55B3 ok > variable amforth ok > $ffff ffxor u. 2366 ok > $ffff fxor u. 2366 ok > fxorsum @ u. 2366 ok > ok > : checkflash $ffff fxor fxorsum @ - u. ; ok > checkflash 0 ok > $ffff ffxor u. B6E3 ok > $ffff fxor u. B6E3 ok > fxorsum @ u. B6E3 ok > ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing. http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Amforth-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/amforth-devel
