| Summary: | 1st Draft OPF ISA WG External RFC ls003: "bigint" operations | ||
|---|---|---|---|
| Product: | Libre-SOC's first SoC | Reporter: | Luke Kenneth Casson Leighton <lkcl> |
| Component: | Specification | Assignee: | Luke Kenneth Casson Leighton <lkcl> |
| Status: | RESOLVED FIXED | ||
| Severity: | enhancement | CC: | libre-soc-isa, programmerjake |
| Priority: | --- | ||
| Version: | unspecified | ||
| Hardware: | PC | ||
| OS: | Linux | ||
| URL: | https://libre-soc.org/openpower/sv/rfc/ls003/ | ||
| See Also: |
https://bugs.libre-soc.org/show_bug.cgi?id=772 https://bugs.libre-soc.org/show_bug.cgi?id=817 https://bugs.libre-soc.org/show_bug.cgi?id=937 https://bugs.libre-soc.org/show_bug.cgi?id=960 |
||
| NLnet milestone: | NLnet.2022-08-051.OPF | total budget (EUR) for completion of task and all subtasks: | 2000 |
| budget (EUR) for this task, excluding subtasks' budget: | 2000 | parent task for budget allocation: | 1009 |
| child tasks for budget allocation: | The table of payments (in EUR) for this task; TOML format: |
[jacob]
amount = 750
submitted = 2023-06-28
paid = 2023-07-12
[lkcl]
amount = 1250
submitted = 2023-06-22
paid = 2023-06-25
|
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| Bug Depends on: | |||
| Bug Blocks: | 960 | ||
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Description
Luke Kenneth Casson Leighton
2023-03-02 12:51:33 GMT
Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net> Date: Thu Mar 2 12:03:01 2023 +0000 add section VA2-Form regs needed update descriptions of dsld and dsrd in ls003 https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=a613a073191df7ba12e445bb49817a18a1da6e90 Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net> Date: Thu Mar 2 13:06:29 2023 +0000 ls003: add to motivation (about dsld and dsrd), correction of "warm words" for dsld and dsrd, proposing four instructions not two https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=f69dec9cf3eff82a11d4444f52ed83be6041ede0 we should probably add maddedus too, since it's the only unsigned*signed mul in powerisa. it's (u64)RA * (i64)RB + (i64)RC note dsld./dsrd. (only the Rc=1 variants) need to be removed because of being 4-in/4-out: https://bugs.libre-soc.org/show_bug.cgi?id=960#c19 lkcl, I'll leave removing Rc from dsld/dsrd for after you've had a chance to confirm that's what we want. meanwhile: commit 1b14f6038a6a6524668ba4a4695f35b1eadac9ff (HEAD -> master, origin/master, origin/HEAD) Good "git" signature for programmerjake@gmail.com with RSA key SHA256:B1iRVvUJkvd7upMIiMqn6OyxvD2SgJkAH3ZnUOj6z+c Author: Jacob Lifshay <programmerjake@gmail.com> Date: Thu Mar 2 21:24:22 2023 -0800 add maddedus to ls003 https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=1b14f6038a6a6524668ba4a4695f35b1eadac9ff commit 93baff679283de184fa11d167fe7517f06ad4877 (HEAD -> master) Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net> Date: Fri Mar 3 10:16:57 2023 +0000 cleanup ls003 - clarify Rc=1 setting overflow, remove comment on divmod2du, add pagebreaks https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=c9eaf69b606abb36577889a8340e2bcec5883171 continuing conversation: https://lists.libre-soc.org/pipermail/libre-soc-dev/2023-March/005519.html (In reply to Jacob Lifshay from comment #5) > lkcl, I'll leave removing Rc from dsld/dsrd for after you've had a chance to > confirm that's what we want. it's not getting removed. (In reply to Luke Kenneth Casson Leighton from comment #7) > (In reply to Jacob Lifshay from comment #5) > > lkcl, I'll leave removing Rc from dsld/dsrd for after you've had a chance to > > confirm that's what we want. > > it's not getting removed. oh, why not? iirc you basically said more than 3-in/2-out was a dealbreaker Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net> Date: Fri Mar 3 10:32:45 2023 +0000 ls003: now 5 instructions being proposed. shorten the words in the observations section to fit onto 1st page https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=0970139d9d2848364c8019a2262b57758107fd78 (In reply to Jacob Lifshay from comment #8) > oh, why not? iirc you basically said more than 3-in/2-out was a dealbreaker for *64-bit* datapaths. CR Fields are 4-bit. although... yeah, a case could be made that the priority is the Dependency Hazard Matrices, and that it's not the size of the datapaths themselves that are the only consideration. 4-in is *definitely* not okay. 3-out (64-bit RT, 64-bit RS, 4-bit CR0) is... dicey. i'm happy to raise it with the ISA WG, to get them to pass it through to IBM's Architects, to see what they think. Author: Luke Kenneth Casson Leighton <lkcl@lkcl.net> Date: Fri Mar 3 10:47:06 2023 +0000 add comment needing resolution in ls003 about 3-in 3-out https://git.libre-soc.org/?p=libreriscv.git;a=commitdiff;h=1da926f056c7f89f0992e5e63da54327886d113d RFC submitted 03mar2023, [[OPF][ISA] #1875] |