[Vm-dev] Aarch64 number bug

Craig Latta craig at blackpagedigital.com
Sun Jun 20 19:48:49 UTC 2021

Hi Ken--

      I brought up a development environment on a Raspberry Pi 4.

 > Unfortunately, my attempt to build a VM simulator on aarch64 fails due
 > to a divide by zero bug.
 > Perhaps because
 >    16r8000000000000000 printStringHex. ==> '0'

      update-eem-463.mcm has a postload action which turns on Sista, 
which recompiles the system, which tries to recompile 
FloatArrayTest>>testFloatArrayPluginPrimitiveAtPut, which exercises this 
very bug during scanning, when trying to create the float 1e-127.

      For now I've rewritten testFloatArrayPluginPrimitiveAtPut and 
testFloatArrayPluginPrimitiveAt on my system to do nothing. When 
building GdbARMv8Plugin, there's some other kind of 
header-include-ordering mayhem, similar to the problem with Linux 
features.h when building the VM. (At least two levels of it, between 
bfd.h and the aarch64 simulator's config.h, and config.h and other 
system headers.) I expect no one has successfully built GdbARMv8Plugin 
on anything but a M1 macOS machine so far.


Craig Latta  ::  research computer scientist
Black Page Digital  ::  Berkeley, California
663137D7940BF5C0AFC :: 1349FB2ADA32C4D5314CE

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