[Milkymist-devel] QEMU/UART and HLT

[Michael Walle]

Hi,

after i fixed some interrupt handling stuff (basically the interrupts never 
gots desasserted interally) the output from userspace to the UART is really 
slow. The kernel messages are processed normally.

It seems, that one character needs one timer tick until it gets passed to the 
UART hardware.

Takeshi, can you have a quick look at your uart driver and test it with the 
HEAD of my qemu-lm32? Maybe my interrupt handling is still fucked up, but on 
the other side, within the kernel the output works as expected.

Besides that, you could add the instruction
  and r0, r0, r0
to idle loop of the kernel. QEMU interprets this opcode as a HLT instruction, 
so it doesn't need 100% cpu on the host system.

-- 
wkr Michael Walle