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arch/arm: add option for FPv4 FPU

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The FPv4-SP FPU is a single-precision FPU with 16 double registers [0]
[1]. It is only available for cortex-m4 cores, and is known to gcc as
fpv4-sp-d16 (note that there is no leading 'v') since gcc-4.5 [2].

[0] https://en.wikipedia.org/wiki/ARM_Cortex-M#Cortex-M4
[1] https://developer.arm.com/docs/ddi0439/latest/floating-point-unit
[2] https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=639cb7b789a54bf78d6ae5e2644450f5eb1837a6

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
This commit is contained in:
Yann E. MORIN 2018-02-25 21:18:15 +01:00 committed by Thomas Petazzoni
parent 7f7701301e
commit 09c6e28233
1 changed files with 20 additions and 0 deletions
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20
arch/Config.in.arm
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@ -40,6 +40,15 @@ config BR2_ARM_CPU_HAS_VFPV4
bool
select BR2_ARM_CPU_HAS_VFPV3
# FPv4 is always optional
config BR2_ARM_CPU_MAYBE_HAS_FPV4
bool
select BR2_ARM_CPU_MAYBE_HAS_FPU
config BR2_ARM_CPU_HAS_FPV4
bool
select BR2_ARM_CPU_HAS_FPU
config BR2_ARM_CPU_HAS_FP_ARMV8
bool
select BR2_ARM_CPU_HAS_VFPV4
@ -460,6 +469,7 @@ config BR2_ARM_ENABLE_NEON
config BR2_ARM_ENABLE_VFP
bool "Enable VFP extension support"
depends on BR2_ARM_CPU_MAYBE_HAS_FPU
select BR2_ARM_CPU_HAS_FPV4 if BR2_ARM_CPU_MAYBE_HAS_FPV4
select BR2_ARM_CPU_HAS_VFPV4 if BR2_ARM_CPU_MAYBE_HAS_VFPV4
select BR2_ARM_CPU_HAS_VFPV3 if BR2_ARM_CPU_MAYBE_HAS_VFPV3
select BR2_ARM_CPU_HAS_VFPV2 if BR2_ARM_CPU_MAYBE_HAS_VFPV2
@ -526,6 +536,7 @@ endchoice
choice
prompt "Floating point strategy"
default BR2_ARM_FPU_FP_ARMV8 if BR2_ARM_CPU_HAS_FP_ARMV8
default BR2_ARM_FPU_FPV4D16 if BR2_ARM_CPU_HAS_FPV4
default BR2_ARM_FPU_VFPV4D16 if BR2_ARM_CPU_HAS_VFPV4
default BR2_ARM_FPU_VFPV3D16 if BR2_ARM_CPU_HAS_VFPV3
default BR2_ARM_FPU_VFPV2 if BR2_ARM_CPU_HAS_VFPV2
@ -636,6 +647,14 @@ config BR2_ARM_FPU_NEON_VFPV4
example on Cortex-A5 and Cortex-A7, support for VFPv4 and
NEON is optional.
config BR2_ARM_FPU_FPV4D16
bool "FPv4-D16"
depends on BR2_ARM_CPU_HAS_FPV4
help
This option allows to use the FPv4-SP (single precision)
floating point unit, as available in some ARMv7m processors
(Cortex-M4).
config BR2_ARM_FPU_FP_ARMV8
bool "FP-ARMv8"
depends on BR2_ARM_CPU_HAS_FP_ARMV8
@ -768,6 +787,7 @@ config BR2_GCC_TARGET_FPU
default "vfpv4-d16" if BR2_ARM_FPU_VFPV4D16
default "neon" if BR2_ARM_FPU_NEON
default "neon-vfpv4" if BR2_ARM_FPU_NEON_VFPV4
default "fpv4-sp-d16" if BR2_ARM_FPU_FPV4D16
default "fp-armv8" if BR2_ARM_FPU_FP_ARMV8
default "neon-fp-armv8" if BR2_ARM_FPU_NEON_FP_ARMV8
depends on BR2_arm || BR2_armeb