[Barrelfish-users] [ARM] About vfp instructions

Wang Nan wangnan0 at huawei.com
Thu May 30 12:41:13 CEST 2013


Some compiler generates vfp instructions such as vpush, vldr for normal code in cpu driver, which introduces complexity (related to fpu state). I propose a patch which disables vfp instructions in cpu
driver code:

diff --git a/hake/ARMv7.hs b/hake/ARMv7.hs
index 142f524..03ed5c4 100644
--- a/hake/ARMv7.hs
+++ b/hake/ARMv7.hs
@@ -116,6 +116,7 @@ kernelCFlags = [ Str s | s <- [ "-fno-builtin",
+				"-mfloat-abi=soft",

On the other hand, vfp and A_SIMD instruction should be allowed in user code, and fpu state should be saved and restored during context switching. In current omap code, I don't find vfp related code.
Does any one can implements them?

Thank you.

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