[Qemu-devel] Re: Accessing the serial port from proll

[Doug Gray <dgray@ucsc.edu>]

Hi,

Thanks for the help.  I've actually tried using the function you 
suggest, but gotten the following error:

sparc-elf-gcc -O1 -W -Wall -DPROLBASE=0xffd00000 -DPROLDATA=0xffd0b000 
-DPROLRODATA=0xffd08000 -D__ANSI__=1 -I../src -mcpu=hypersparc 
-Wa,-xarch=v8 -g -DQEMU -m32 -fno-builtin -c main.c
sparc-elf-ld -N -Ttext 0xffd00000 --section-start .rodata=0xffd08000 
-Tdata 0xffd0b000 -Tbss 0xffd0b000 -o proll.elf head.o wuf.o wof.o 
main.o  printf.o le.o system_qemu.o iommu.o arp.o netinit.o bootp.o 
packet.o tftp.o udp.o sched_4m.o openprom.o vconsole.o hconsole.o 
rconsole.o vcons_zs.o esp.o
sparc-elf-ld: section .rodata [00000000ffd08000 -> 00000000ffd0a129] 
overlaps section .text [00000000ffd00000 -> 00000000ffd08077]
sparc-elf-ld: proll.elf: section .rodata lma 0xffd08000 overlaps 
previous sections
make: *** [proll.elf] Error 1

However when I tried your code snippet it works fine.  It seems that it 
only works if I call that function from an infinite loop (big loop or 
loops with a break statement don't compile either), which is driving me 
nuts.  Do you know why this is?

Also, some additional background info.  I am actually using the 
-nographic option.  This project is for a grad class on computer 
architecture.  The prof. says he has a sparc processor implemented on an 
fpga and wants to load linux on it, but it doesn't have a hard drive or 
network connection, so that is why I'm writing a serial loader.

-Doug