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Groups > comp.lang.forth > #134983
| From | peter <peter.noreply@tin.it> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: FP stack depth limitations (was: Coroutines in Forth) |
| Date | 2026-04-26 09:57 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <20260426095752.00006baa@tin.it> (permalink) |
| References | (10 earlier) <87jytv4kkl.fsf@nightsong.com> <69ecae51$1@news.ausics.net> <nnd$42cc93d2$5992367b@fb99b8b872c17312> <877bpu49d1.fsf@nightsong.com> <2026Apr26.075504@mips.complang.tuwien.ac.at> |
On Sun, 26 Apr 2026 05:55:04 GMT anton@mips.complang.tuwien.ac.at (Anton Ertl) wrote: > Paul Rubin <no.email@nospam.invalid> writes: > >Hans Bezemer <the.beez.speaks@gmail.com> writes: > >> We do have N>R (https://forth-standard.org/standard/tools/NtoR). So if > >> the whole problem is "there is no more room on the FP stack", there is > >> a way out. > > > >That must be pretty new (it's not in gforth 0.7.3) > > It was accepted into Forth-200x at the 2010 standards meeting. > > >so I wonder how > >helpful it really is. > > We have two uses in the Gforth sources. I.e., not particularly > useful. > > In any case, it does not help with FP stack limitations at all, > because N>R transfers cells from the data stack to the return stack. > > My take on FP stack depth limitations in some systems is that you use > as much FP stack as you need, and a Forth system (like Gforth) where > you can make the FP stack as deep as available memory and address > space permit, and publish that. Maybe it will inspire the system > implementors with shallow FP stacks to provide deep FP stacks, at > least optionally. > > However, when I did something that required a deep FP stack (adding up > an array with pairwise addition > <2025Jul16.132504@mips.complang.tuwien.ac.at>), I actually worked > around the limitations of systems that only provide a shallow FP > stack. But that was easy enough in that case. > > Concerning systems with FP stack limits, AFAIK VFX has FP packages > that support very deep stacks, including the SSE-based package that > used to be the default in VFX64 for a while. > > iForth implements a deep stack: it uses the 387 stack within a > definition and stores the FP stack items that are on the 387 stack to > memory on calls, and if the FP stack would overflow from the > computations within a word. I think this is a good approach: Much FP > computation time is spent in words that do not call other words, or at > least the FP stack items do not live across the calls. iForth seems > to overdo it, however, even code like > > : bar > dup f@ cell+ dup f@ cell+ dup f@ cell+ > dup f@ cell+ dup f@ cell+ dup f@ cell+ > f+ f+ f+ f+ f+ ; > > which uses only 6 FP stack items does not produce the obvious code, > but something significantly longer: It first performs 6 FLD > instructions corresponding to the 6 F@, then stores 4 FP items, > presumably on the memory FP stack, and only then starts the additions > (interleaved with some other code). > > - anton lxf uses the cpu FP stack. I think that is one of the worse decisions I made for it. It will fail on all but the simplest complex fp math operations. For lxf64 a priority was to have a separate in memory FP stack. It has worked out very well! You bar example becomesseea bar 0x4282B0 C5FB100B vmovsd xmm1, qword [rbx] 0x4282B4 4883C308 add rbx, 0x8 0x4282B8 C5FB1013 vmovsd xmm2, qword [rbx] 0x4282BC 4883C308 add rbx, 0x8 0x4282C0 C5FB101B vmovsd xmm3, qword [rbx] 0x4282C4 4883C308 add rbx, 0x8 0x4282C8 C5FB1023 vmovsd xmm4, qword [rbx] 0x4282CC 4883C308 add rbx, 0x8 0x4282D0 C5FB102B vmovsd xmm5, qword [rbx] 0x4282D4 4883C308 add rbx, 0x8 0x4282D8 C5FB1033 vmovsd xmm6, qword [rbx] 0x4282DC 4883C308 add rbx, 0x8 0x4282E0 C5CB58F5 vaddsd xmm6, xmm6, xmm5 0x4282E4 C5CB58F4 vaddsd xmm6, xmm6, xmm4 0x4282E8 C5CB58F3 vaddsd xmm6, xmm6, xmm3 0x4282EC C5CB58F2 vaddsd xmm6, xmm6, xmm2 0x4282F0 C5CB58F1 vaddsd xmm6, xmm6, xmm1 0x4282F4 C4C17B1145F8 vmovsd qword [r13-0x8], xmm0 0x4282FA C5FB10C6 vmovsd xmm0, xmm0, xmm6 0x4282FE 4D8D6DF8 lea r13, [r13-0x8] 0x428302 C3 ret 83 bytes, 21 instructions As seen all the fp registers can be put to good use! BR Peter
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Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-05 23:25 +0100
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-05 23:30 +0100
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-05 17:16 -0700
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-06 19:58 +0100
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-22 11:13 -0700
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-22 22:05 +0200
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-07 13:23 +0200
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-06 13:51 +0200
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-06 22:20 +0100
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-07 13:35 +0200
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-07 20:55 +0100
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-08 12:34 +0200
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 12:32 +0100
Re: Coroutines in Forth Stephen Pelc <stephen@vfxforth.com> - 2026-04-09 10:12 +0000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-10 19:01 +0200
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-11 11:54 +1000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-05-01 13:07 +0200
Re: Coroutines in Forth peter <peter.noreply@tin.it> - 2026-04-11 09:49 +0200
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-11 22:03 +0200
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-12 12:49 +1000
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-12 12:13 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-12 17:39 +0200
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-13 10:54 +1000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-13 19:24 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-12 13:48 +0200
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-13 12:13 +0200
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-22 11:18 -0700
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-23 11:13 +1000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-23 12:37 +0200
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-24 10:36 -0700
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-25 12:12 +1000
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-24 23:31 -0700
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-25 10:45 +0200
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-25 22:06 +1000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-25 15:11 +0200
Re: Coroutines in Forth dxf <dxforth@gmail.com> - 2026-04-26 13:33 +1000
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-26 16:28 +0200
Re: Coroutines in Forth Paul Rubin <no.email@nospam.invalid> - 2026-04-25 21:46 -0700
FP stack depth limitations (was: Coroutines in Forth) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-26 05:55 +0000
Re: FP stack depth limitations Paul Rubin <no.email@nospam.invalid> - 2026-04-26 00:28 -0700
Re: FP stack depth limitations dxf <dxforth@gmail.com> - 2026-04-26 19:55 +1000
Re: FP stack depth limitations (was: Coroutines in Forth) peter <peter.noreply@tin.it> - 2026-04-26 09:57 +0200
Re: FP stack depth limitations (was: Coroutines in Forth) albert@spenarnc.xs4all.nl - 2026-04-26 14:34 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-25 15:01 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-05-01 13:13 +0200
Forth, C, hardware, and programming virtues (was: Coroutines in Forth) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 05:26 +0000
Re: Forth, C, hardware, and programming virtues Paul Rubin <no.email@nospam.invalid> - 2026-04-24 23:55 -0700
Re: Forth, C, hardware, and programming virtues anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 08:21 +0000
Re: Forth, C, hardware, and programming virtues albert@spenarnc.xs4all.nl - 2026-04-25 11:27 +0200
Re: Forth, C, hardware, and programming virtues Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-25 15:43 +0200
Re: Forth, C, hardware, and programming virtues anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 17:21 +0000
Re: Forth, C, hardware, and programming virtues dxf <dxforth@gmail.com> - 2026-04-26 15:21 +1000
Re: Forth, C, hardware, and programming virtues Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-26 15:08 +0200
Re: Forth, C, hardware, and programming virtues albert@spenarnc.xs4all.nl - 2026-04-26 00:34 +0200
Re: Forth, C, hardware, and programming virtues Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-26 15:10 +0200
locals (was: Coroutines in Forth) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 04:47 +0000
Re: locals Paul Rubin <no.email@nospam.invalid> - 2026-04-24 23:21 -0700
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 06:43 +0000
Re: locals albert@spenarnc.xs4all.nl - 2026-04-25 11:43 +0200
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-25 10:22 +0000
Re: locals peter <peter.noreply@tin.it> - 2026-04-25 16:07 +0200
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-25 17:38 +0200
Re: locals albert@spenarnc.xs4all.nl - 2026-04-26 01:13 +0200
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-26 14:03 +0000
Re: locals peter <peter.noreply@tin.it> - 2026-04-27 09:31 +0200
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-27 07:53 +0000
Re: locals peter <peter.noreply@tin.it> - 2026-04-27 11:52 +0200
Re: locals albert@spenarnc.xs4all.nl - 2026-04-26 00:51 +0200
Re: locals Paul Rubin <no.email@nospam.invalid> - 2026-04-25 22:40 -0700
Re: locals albert@spenarnc.xs4all.nl - 2026-04-26 14:55 +0200
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-26 09:50 +0000
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-26 16:22 +0200
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-26 17:04 +0000
Re: locals dxf <dxforth@gmail.com> - 2026-04-27 11:51 +1000
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-28 08:21 +0200
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-28 08:22 +0200
Re: locals dxf <dxforth@gmail.com> - 2026-04-27 11:12 +1000
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-28 14:34 +0200
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-28 14:34 +0200
Re: locals Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-29 12:44 +0100
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-29 14:37 +0200
Re: locals Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-29 14:44 +0200
Re: locals Paul Rubin <no.email@nospam.invalid> - 2026-05-01 23:50 -0700
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-02 10:34 +0000
Re: locals Paul Rubin <no.email@nospam.invalid> - 2026-05-01 23:54 -0700
Re: locals dxf <dxforth@gmail.com> - 2026-05-02 17:36 +1000
Re: locals Paul Rubin <no.email@nospam.invalid> - 2026-05-02 01:11 -0700
Re: locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-05-02 15:58 +0000
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-07 09:28 -0500
Re: Coroutines in Forth anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2026-04-07 16:12 +0000
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-07 18:06 -0500
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 11:43 +0100
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-08 13:16 +0200
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-08 11:47 -0500
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 21:48 +0100
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-09 07:06 -0500
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-09 16:41 +0200
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-09 13:34 -0500
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-10 01:23 +0200
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-09 21:34 -0500
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-09 13:01 +0200
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-09 07:01 -0500
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-09 16:10 +0200
Re: Coroutines in Forth Krishna Myneni <krishna.myneni@ccreweb.org> - 2026-04-09 13:29 -0500
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 21:26 +0100
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-08 14:22 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-28 15:31 +0200
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-29 10:49 +0200
Re: Coroutines in Forth Hans Bezemer <the.beez.speaks@gmail.com> - 2026-04-29 15:22 +0200
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 11:33 +0100
Re: Coroutines in Forth albert@spenarnc.xs4all.nl - 2026-04-08 13:07 +0200
Re: Coroutines in Forth Gerry Jackson <do-not-use@swldwa.uk> - 2026-04-08 22:05 +0100
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