ARM: Use local versions of libgcc functions instead of linking against libgcc.

The flags used to compile libgcc may make it incompatible with the code it's
linked against, and/or the hardware it's going to run on. Rather than try to
tease the right libgcc from the compiler, lets just leave it out and use our
own implementations of the necessary functions.

Most of these implementations were taken from the Linux kernel, except for
uldivmod.S which was taken from a CL originally written for U-Boot by
Che-Liang Chiou in December of 2010. It was modified to not use the CLZ
instruction on machines that don't have it, anything earlier than ARMv5. The
top block was taken from an earlier version of the same CL which didn't use
CLZ in that spot. The later block was written from scratch.

TEST=Built and booted into the bootblock on nyan. Ran a series of tests which
divided and modded a 64 bit value by various 32 bit values which were powers
of 2. Confirmed that this function was used and that the returned value was
correct. Printed decimal and hex versions of some values and verified that
they equaled each other. Built and booted on pit with serial enabled.

Change-Id: I7527e28af411b7aa7f94579be95a6b352a91a224
Signed-off-by: Gabe Black <>
Reviewed-by: David Hendricks <>
Commit-Queue: Gabe Black <>
Tested-by: Gabe Black <>
13 files changed