[U-Boot] [PATCH] ARM: Add comments why -msoft-float is used.

Alexander Holler holler at ahsoftware.de
Sun Feb 20 04:12:12 CET 2011 

Without -msoft-float the compiler would be allowed to use certain
floating-point instructions (VFP/NEON) e.g. for optimizations, which
would require additional code, for example to save contexts for
interrupts. Add a comment which describes this in short words.

Signed-off-by: Alexander Holler <holler at ahsoftware.de>
---
 arch/arm/cpu/arm1136/config.mk           |    2 ++
 arch/arm/cpu/arm1176/config.mk           |    2 ++
 arch/arm/cpu/arm1176/s3c64xx/config.mk   |    2 ++
 arch/arm/cpu/arm720t/config.mk           |    1 +
 arch/arm/cpu/arm920t/config.mk           |    1 +
 arch/arm/cpu/arm925t/config.mk           |    1 +
 arch/arm/cpu/arm926ejs/config.mk         |    1 +
 arch/arm/cpu/arm926ejs/davinci/config.mk |    1 +
 arch/arm/cpu/arm946es/config.mk          |    1 +
 arch/arm/cpu/arm_intcm/config.mk         |    1 +
 arch/arm/cpu/armv7/config.mk             |    2 ++
 arch/arm/cpu/armv7/omap-common/config.mk |    2 ++
 arch/arm/cpu/ixp/config.mk               |    1 +
 arch/arm/cpu/lh7a40x/config.mk           |    1 +
 arch/arm/cpu/pxa/config.mk               |    1 +
 arch/arm/cpu/s3c44b0/config.mk           |    1 +
 arch/arm/cpu/sa1100/config.mk            |    1 +
 17 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/arch/arm/cpu/arm1136/config.mk b/arch/arm/cpu/arm1136/config.mk
index 3e68535..e2c32c0 100644
--- a/arch/arm/cpu/arm1136/config.mk
+++ b/arch/arm/cpu/arm1136/config.mk
@@ -20,6 +20,8 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
+
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
diff --git a/arch/arm/cpu/arm1176/config.mk b/arch/arm/cpu/arm1176/config.mk
index 14346cf..a9a36b4 100644
--- a/arch/arm/cpu/arm1176/config.mk
+++ b/arch/arm/cpu/arm1176/config.mk
@@ -20,6 +20,8 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
+
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
diff --git a/arch/arm/cpu/arm1176/s3c64xx/config.mk b/arch/arm/cpu/arm1176/s3c64xx/config.mk
index 14346cf..a9a36b4 100644
--- a/arch/arm/cpu/arm1176/s3c64xx/config.mk
+++ b/arch/arm/cpu/arm1176/s3c64xx/config.mk
@@ -20,6 +20,8 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
+
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
diff --git a/arch/arm/cpu/arm720t/config.mk b/arch/arm/cpu/arm720t/config.mk
index 3844c62..1d59f60 100644
--- a/arch/arm/cpu/arm720t/config.mk
+++ b/arch/arm/cpu/arm720t/config.mk
@@ -22,6 +22,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS +=  -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi
diff --git a/arch/arm/cpu/arm920t/config.mk b/arch/arm/cpu/arm920t/config.mk
index 8f6c1a3..b595088 100644
--- a/arch/arm/cpu/arm920t/config.mk
+++ b/arch/arm/cpu/arm920t/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
diff --git a/arch/arm/cpu/arm925t/config.mk b/arch/arm/cpu/arm925t/config.mk
index 8f6c1a3..b595088 100644
--- a/arch/arm/cpu/arm925t/config.mk
+++ b/arch/arm/cpu/arm925t/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
diff --git a/arch/arm/cpu/arm926ejs/config.mk b/arch/arm/cpu/arm926ejs/config.mk
index f8ef90f..fb83862 100644
--- a/arch/arm/cpu/arm926ejs/config.mk
+++ b/arch/arm/cpu/arm926ejs/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv5te
diff --git a/arch/arm/cpu/arm926ejs/davinci/config.mk b/arch/arm/cpu/arm926ejs/davinci/config.mk
index 565adda..081c13d 100644
--- a/arch/arm/cpu/arm926ejs/davinci/config.mk
+++ b/arch/arm/cpu/arm926ejs/davinci/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv5te
diff --git a/arch/arm/cpu/arm946es/config.mk b/arch/arm/cpu/arm946es/config.mk
index e783f69..f7db925 100644
--- a/arch/arm/cpu/arm946es/config.mk
+++ b/arch/arm/cpu/arm946es/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
diff --git a/arch/arm/cpu/arm_intcm/config.mk b/arch/arm/cpu/arm_intcm/config.mk
index e783f69..f7db925 100644
--- a/arch/arm/cpu/arm_intcm/config.mk
+++ b/arch/arm/cpu/arm_intcm/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
diff --git a/arch/arm/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk
index 49ac9c7..03ec32b 100644
--- a/arch/arm/cpu/armv7/config.mk
+++ b/arch/arm/cpu/armv7/config.mk
@@ -20,6 +20,8 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
+
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v7a.
diff --git a/arch/arm/cpu/armv7/omap-common/config.mk b/arch/arm/cpu/armv7/omap-common/config.mk
index 49ac9c7..03ec32b 100644
--- a/arch/arm/cpu/armv7/omap-common/config.mk
+++ b/arch/arm/cpu/armv7/omap-common/config.mk
@@ -20,6 +20,8 @@
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 # MA 02111-1307 USA
 #
+
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v7a.
diff --git a/arch/arm/cpu/ixp/config.mk b/arch/arm/cpu/ixp/config.mk
index deca3f4..9634615 100644
--- a/arch/arm/cpu/ixp/config.mk
+++ b/arch/arm/cpu/ixp/config.mk
@@ -24,6 +24,7 @@
 
 BIG_ENDIAN = y
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float -mbig-endian
 
 PLATFORM_CPPFLAGS += -mbig-endian -march=armv5te -mtune=strongarm1100
diff --git a/arch/arm/cpu/lh7a40x/config.mk b/arch/arm/cpu/lh7a40x/config.mk
index 47b2b7b..6c4fa54 100644
--- a/arch/arm/cpu/lh7a40x/config.mk
+++ b/arch/arm/cpu/lh7a40x/config.mk
@@ -21,6 +21,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
diff --git a/arch/arm/cpu/pxa/config.mk b/arch/arm/cpu/pxa/config.mk
index a05d69c..45405d6 100644
--- a/arch/arm/cpu/pxa/config.mk
+++ b/arch/arm/cpu/pxa/config.mk
@@ -22,6 +22,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv5te -mtune=xscale
diff --git a/arch/arm/cpu/s3c44b0/config.mk b/arch/arm/cpu/s3c44b0/config.mk
index 7454d72..6a374a7 100644
--- a/arch/arm/cpu/s3c44b0/config.mk
+++ b/arch/arm/cpu/s3c44b0/config.mk
@@ -22,6 +22,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi -msoft-float
diff --git a/arch/arm/cpu/sa1100/config.mk b/arch/arm/cpu/sa1100/config.mk
index 6f21f41..e52e8b0 100644
--- a/arch/arm/cpu/sa1100/config.mk
+++ b/arch/arm/cpu/sa1100/config.mk
@@ -22,6 +22,7 @@
 # MA 02111-1307 USA
 #
 
+# -msoft-float forces the compiler to not use any fp-related instructions.
 PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=strongarm1100
-- 
1.7.3.4

More information about the U-Boot mailing list