From 5cc1c7b594d97245d2feffbe14478b15f4e48db8 Mon Sep 17 00:00:00 2001 From: Jonathan 'theJPster' Pallant Date: Fri, 11 Oct 2024 13:55:17 +0200 Subject: [PATCH] Note Integer MVE hard-float use-case in arm platform docs. --- .../rustc/src/platform-support/thumbv8m.main-none-eabi.md | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/doc/rustc/src/platform-support/thumbv8m.main-none-eabi.md b/src/doc/rustc/src/platform-support/thumbv8m.main-none-eabi.md index 40b19364f61c..82fdc5b21cf2 100644 --- a/src/doc/rustc/src/platform-support/thumbv8m.main-none-eabi.md +++ b/src/doc/rustc/src/platform-support/thumbv8m.main-none-eabi.md @@ -74,6 +74,11 @@ to use these flags. | Cortex-M85 | DP | Yes | Int | `cortex-m85` | `-mve.fp` | | Cortex-M85 | DP | Yes | Int+Float | `cortex-m85` | None | +*Technically* you can use this hard-float ABI on a CPU which has no FPU but does +have Integer MVE, because MVE provides the same set of registers as the FPU +(including `s0` and `d0`). The particular set of flags that might enable this +unusual scenario are currently not recorded here. +
Never use the `-fpregs` *target-feature* with the `thumbv8m.main-none-eabihf`