georg, 1. could please show a piece of c code which can be compiled to the redundant asm ? as simple & short as possible.
2. you are welcome to create patch tickets on sourceforge with any stm8 optimized functions. ben -- 发自我的网易邮箱手机智能版 在 2014-10-02 22:57:08，"Georg Ottinger" <ge...@otelo.or.at> 写道： >ok - after figuring out that A is 8Bit wide (what i should have expected >on an 8Bit arch) - i have two proposals for Peephole optimizations. > >1.) > >ld a,(x) >ld xl,a >inc (direct) >ld a,xl >ret > >to > >ld a,(x) >inc (direct) >ret > >2.) > >ld xl, a >ld a, xh > >to > >rlwa (rotate word left through accumulator) > >(under the condition that the current content of xh is not used elsewhere) > >the same can be achived the other way round with RRWA > > >Am 2014-10-02 um 16:29 schrieb Georg Ottinger: >> hmm ... >> >> is ld a, (x) on stm8 a byte wise operation??? >> >> >> >> Am 2014-10-02 um 16:10 schrieb Georg Ottinger: >>> I just figured out that >>> s >>> ld a,(x) >>> ld xl, a >>> ld a, xl >>> >>> acutally is usefull code - to zero the Upper Byte of A .... >>> >>> >>> >>> Am 2014-10-02 um 16:03 schrieb Georg Ottinger: >>>> congrats to Ben Shi - his lastest patch - just shrunk my firmware from >>>> 4210 Bytes to 4039 Bytes thanks to _mullong_stm8 >>>> >>>> I had a look at the asm code of my project and there more points where >>>> optimization could be achived. - maybe I can convince someone to give it >>>> a try - as I am not an expert to do this ;) >>>> >>>> for example an optimized _divulong routine - which should be >>>> interessting as the STM8 has a hardware divder instruction. >>>> >>>> I also make use of _strncmp which could be optimzed but maybe that is >>>> not so promising. >>>> >>>> I also noted some parts which could be optimized via peeps.def: >>>> >>>> >>>> 000052 F6 [ 1] 126 ld a, (x) >>>> 000053 97 [ 1] 127 ld xl, a >>>> 128 ; rx_ringbuffer.c: 65: rx_tail++; >>>> 000054 72 5Cu01u01 [ 1] 129 inc _rx_tail+0 >>>> 130 ; rx_ringbuffer.c: 67: return temp; >>>> 000058 9F [ 1] 131 ld a, xl >>>> 000059 81 [ 4] 132 ret >>>> >>>> >>>> => I think that the "131 ld a,xl" instruction could be omited - but I >>>> have no Idea how to craft a peephole definition for this case. >>>> >>>> >>>> best wishes, Georg >>>> >> >> ------------------------------------------------------------------------------ >> Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer >> Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports >> Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper >> Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer >> http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk >> _______________________________________________ >> Sdcc-user mailing list >> Sdcc-user@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/sdcc-user > > >------------------------------------------------------------------------------ >Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer >Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports >Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper >Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer >http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk >_______________________________________________ >Sdcc-user mailing list >Sdcc-user@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/sdcc-user ------------------------------------------------------------------------------ Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk _______________________________________________ Sdcc-user mailing list Sdcc-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/sdcc-user
