On Sat, 11 Sep 2010, pito wrote: > push R0 ; worst case - store everything > push R1 > push R2 > ..... > push R31
Please be careful NOT to restore r28, r29 (register Y - your data stack pointer) and r24, r25 - top of your stack. > > ld R10, Y+ > ld R11, Y+ ; takes c from stack > > ld R12, Y+ > ld R13, Y+ ; takes b from stack > > ld R14, Y+ > ld R15, Y+ ; takes a from stack This is wrong - TOS is in r26:r25 (tosh:tosl) *NOT* in RAM! > st -Y, R16 > st -Y, R17 ; puts m on stack > > st -Y, R18 > st -Y, R19 ; puts l on stack > > st -Y, R20 > st -Y, R21 ; puts k on stack Same as above - just leave TOS in r26:r25 and don't restore it via pop: > pop R31 ; worst case housekeeping > .... > pop R2 > pop R1 > pop R0 Don't restore tosl, tosh, Y (r24, r25, r28, r29) - since then your stack effects will be void (or just corrupted). No need to save temp0..temp5 (r14, r15, r16, r17, r18, r19, r20, r21). r30 and r31 (zl, zh) are used as a scratchapad register, so no need to save these too. r2 and r3 should be zero, so no need to save that on stack (use it or restore it to zero at exit). (Matthias: I noticed that techdoc says R22:R23 are TOS and R24:R25 are W, in my case on ATmega328P it's the other way around) Please keep in mind that machine stack is not indefinite (64 bytes only). So if your routine is pushing something on stack and doing some calls it can get tight. Regarding you other email, regarding "here", "dp" etc. DP and HERE are stored in EEPROM (in my case EEPROM address $6 and $8, respectively), please see PFA_EFETCH how to read EEPROM from assembly or push them on the data stack before running your asm routing as parameters. --Marcin ------------------------------------------------------------------------------ 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 Amforth-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/amforth-devel
