github-mirrors/neorv32
1
0
Fork 0
mirror of https://github.com/stnolting/neorv32.git synced 2025-04-24 22:27:21 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

[docs] add CFU min/max execution cycles

Browse source
This commit is contained in:
stnolting 2024-10-02 21:00:41 +02:00
parent 2449967d26
commit beea2456fb
1 changed files with 14 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

14
docs/datasheet/cpu.adoc
View file

@ -1051,6 +1051,20 @@ see section <<_custom_functions_unit_cfu>>.
Software can utilize the custom instructions by using _intrinsics_, which are basically inline assembly functions that
behave like regular C functions but that evaluate to a single custom instruction word (no calling overhead at all).
.CFU Execution Time
[NOTE]
The actual CFU execution time depends on the logic being implemented. The CPU architecture requires a minimal execution
time of 3 cycle and automatically terminates execution after 512 cycles if the CFU does not complete operation within
this time window.
.Instructions and Timing
[cols="<2,<5,<2"]
[options="header", grid="rows"]
|=======================
| Class | Instructions | Execution cycles
| Custom instructions | Instruction words with `custom-0` or `custom-1` opcode | 3 ... 3+512
|=======================
==== `Smpmp` ISA Extension