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Groups > comp.lang.forth > #55357
| From | Cecil Bayona <cbayona@cbayona.com> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: esp8266 eForth and it's development software |
| Date | 2017-03-01 22:44 -0600 |
| Organization | A noiseless patient Spider |
| Message-ID | <o987s3$upp$1@dont-email.me> (permalink) |
| References | (7 earlier) <87bmtkfnkq.fsf@nightsong.com> <o981bq$n4c$1@dont-email.me> <877f48fkqx.fsf@nightsong.com> <o982o4$ib3$1@dont-email.me> <8737ewfist.fsf@nightsong.com> |
On 3/1/2017 9:40 PM, Paul Rubin wrote:
> Cecil Bayona <cbayona@cbayona.com> writes:
>> IP = data(IP / sizeof(w));
>
> You've inspected the asm code and there's really a division there?
>
> Why not just change it to a shift?
>
In some cases it uses shift in a few cases it uses divide, below is an
example where it uses shift, it's pretty hard to find anything as the
code is all mixed up with libraries in between routines;
void cellsl(void) {
top /= sizeof(w);
40201c60: fffc31 l32r a3, 40201c50 <_Z22__run_user_rf_pre_initv+0x4>
40201c63: fffe51 l32r a5, 40201c5c
<_Z22__run_user_rf_pre_initv+0x10>
40201c66: 0328 l32i.n a2, a3, 0
40201c68: 424b addi.n a4, a2, 4
40201c6a: 0349 s32i.n a4, a3, 0
40201c6c: fffa41 l32r a4, 40201c54 <_Z22__run_user_rf_pre_initv+0x8>
40201c6f: 0438 l32i.n a3, a4, 0
40201c71: 1239 s32i.n a3, a2, 4
40201c73: fff921 l32r a2, 40201c58 <_Z22__run_user_rf_pre_initv+0xc>
40201c76: 0238 l32i.n a3, a2, 0
40201c78: 416230 srli a6, a3, 2
40201c7b: a05650 addx4 a5, a6, a5
40201c7e: 0558 l32i.n a5, a5, 0
40201c80: 334b addi.n a3, a3, 4
40201c82: 0459 s32i.n a5, a4, 0
40201c84: 0239 s32i.n a3, a2, 0
40201c86: f00d ret.n
An awful lot of code to store a number shifted right twice;
Looking at the code generated there is so much code to do something very
simple that a divide would hardly be any worse, it has multiply and
divide instructions built in.
"top" is the cached top of the Data Stack so its replacing the top of
the Data Stack with itself shifted right 2 places.
--
Cecil - k5nwa
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esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 15:18 -0600
Re: esp8266 eForth and it's development software David Schultz <abuse@127.0.0.1> - 2017-03-01 15:29 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 17:16 -0600
Re: esp8266 eForth and it's development software David Schultz <abuse@127.0.0.1> - 2017-03-01 17:51 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 18:36 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 16:53 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 19:28 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 17:56 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 20:53 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 18:57 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 21:17 -0600
Re: esp8266 eForth and it's development software David Schultz <abuse@127.0.0.1> - 2017-03-01 21:38 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 22:02 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 19:40 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 22:44 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 14:50 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 17:26 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-01 15:41 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-01 18:10 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-04 20:50 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-04 20:10 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-04 23:06 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-04 21:25 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-05 00:47 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-05 01:36 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-05 17:11 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-05 15:43 -0600
Re: esp8266 eForth and it's development software Mark Wills <markwills1970@gmail.com> - 2017-03-06 01:45 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-06 10:44 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-06 12:28 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-06 16:00 -0600
Re: esp8266 eForth and it's development software Rod Pemberton <NeedNotReplyHere@xrsevnneqk.cem> - 2017-03-06 17:57 -0500
Re: esp8266 eForth and it's development software Mark Wills <markwills1970@gmail.com> - 2017-03-07 01:23 -0800
Re: esp8266 eForth and it's development software albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-07 12:32 +0100
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-07 10:39 -0600
Re: esp8266 eForth and it's development software albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-06 13:35 +0100
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-06 10:51 -0600
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-07 22:33 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-07 20:39 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-07 23:42 -0600
Re: esp8266 eForth and it's development software Paul Rubin <no.email@nospam.invalid> - 2017-03-07 23:44 -0800
Re: esp8266 eForth and it's development software Cecil Bayona <cbayona@cbayona.com> - 2017-03-08 11:03 -0600
Re: esp8266 eForth and it's development software albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-08 12:05 +0100
Re: esp8266 eForth and it's development software anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-03-06 17:09 +0000
Re: esp8266 eForth and it's development software albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-03-07 12:52 +0100
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