From: lkcl Date: Tue, 1 Mar 2022 16:58:04 +0000 (+0000) Subject: (no commit message) X-Git-Tag: opf_rfc_ls005_v1~3166 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b94c8fe5d05e24b4313fc42cbb30a77e115d1d7a;p=libreriscv.git --- diff --git a/openpower/openpower/whitepapers/microcontroller_power_isa_for_ai.mdwn b/openpower/openpower/whitepapers/microcontroller_power_isa_for_ai.mdwn index b86f08272..515bb08b6 100644 --- a/openpower/openpower/whitepapers/microcontroller_power_isa_for_ai.mdwn +++ b/openpower/openpower/whitepapers/microcontroller_power_isa_for_ai.mdwn @@ -6,10 +6,10 @@ in between attempting to compile microwatt and Libre-SOC for an 85k LUT4 FPGA wh the difference was an astounding 1.4 to 1. -* the MUL pipeline dropped an astonishing 75% which given that multiply is O(N^2) is not surprising +* the MUL pipeline dropped an astonishing 75% which given that multiply is O(N^2) is, retrospectively, not surprising * SHIFT dropped to 50% * ALU (add) dropped over 50% -* Logical dropped significantly +* Logical dropped over 60% * BRAM usage dropped by over 75% i then took a look at the I-Cache, D-Cache and MMU, and i am not seeing any practical barriers to setting them to 32 bit either, other than needing to define a new RADIX32 data format, which looks to be as simple as reducing the PTE and PDE lengths. @@ -34,7 +34,7 @@ The high resource utilisation is (including for Libre-BMC) pressurising everyone it is also worth reiterating that larger designs give FPGA tools a much harder job, dramatically reducing the maximum achievable clock rate. -a 32 bit implementation of a MMU-capable Power ISA core could easily fit into a lower cost Digilent Arty A7-35t, a 45K LUT4 VERSA_ECP5, and with a little corner-cutting (no MMU/L1) even potentially fit into the low-cost 25K orangecrab with plenty of room. +based on the above analysis, a 32 bit implementation of a MMU-capable Power ISA core could easily fit into a lower cost Digilent Arty A7-35t, a 45K LUT4 VERSA_ECP5, and with a little corner-cutting (no MMU/L1) even potentially fit into the low-cost 25K orangecrab with plenty of room. this would make it affordable and accessible to e.g. students in India as well as increase general adoption