qemu-e2k

History

Emilio G. Cota c5a49c63fa tcg: convert tb->cflags reads to tb_cflags(tb) Convert all existing readers of tb->cflags to tb_cflags, so that we use atomic_read and therefore avoid undefined behaviour in C11. Note that the remaining setters/getters of the field are protected by tb_lock, and therefore do not need conversion. Luckily all readers access the field via 'tb->cflags' (so no foo.cflags, bar->cflags in the code base), which makes the conversion easily scriptable: FILES=$(git grep 'tb->cflags' target include/exec/gen-icount.h \ accel/tcg/translator.c \| cut -f1 -d':' \| sort \| uniq) perl -pi -e 's/([^.>])tb->cflags/$1tb_cflags(tb)/g' $FILES perl -pi -e 's/([a-z->.]*)(->\|\.)tb->cflags/tb_cflags($1$2tb)/g' $FILES Then manually fixed the few errors that checkpatch reported. Compile-tested for all targets. Suggested-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>		2017-10-24 13:53:41 -07:00
..
cpu-qom.h
cpu.c	qom: Introduce CPUClass.tcg_initialize	2017-10-24 22:00:13 +02:00
cpu.h	lm32: replace cpu_lm32_init() with cpu_generic_init()	2017-09-01 11:54:25 -03:00
gdbstub.c
helper.c	lm32: replace cpu_lm32_init() with cpu_generic_init()	2017-09-01 11:54:25 -03:00
helper.h
lm32-semi.c
machine.c
Makefile.objs
op_helper.c
README
TODO
translate.c	tcg: convert tb->cflags reads to tb_cflags(tb)	2017-10-24 13:53:41 -07:00

README

LatticeMico32 target
--------------------

General
-------
All opcodes including the JUART CSRs are supported.


JTAG UART
---------
JTAG UART is routed to a serial console device. For the current boards it
is the second one. Ie to enable it in the qemu virtual console window use
the following command line parameters:
  -serial vc -serial vc
This will make serial0 (the lm32_uart) and serial1 (the JTAG UART)
available as virtual consoles.


Semihosting
-----------
Semihosting on this target is supported. Some system calls like read, write
and exit are executed on the host if semihosting is enabled. See
target/lm32-semi.c for all supported system calls. Emulation aware programs
can use this mechanism to shut down the virtual machine and print to the
host console. See the tcg tests for an example.


Special instructions
--------------------
The translation recognizes one special instruction to halt the cpu:
  and r0, r0, r0
On real hardware this instruction is a nop. It is not used by GCC and
should (hopefully) not be used within hand-crafted assembly.
Insert this instruction in your idle loop to reduce the cpu load on the
host.


Ignoring the MSB of the address bus
-----------------------------------
Some SoC ignores the MSB on the address bus. Thus creating a shadow memory
area. As a general rule, 0x00000000-0x7fffffff is cached, whereas
0x80000000-0xffffffff is not cached and used to access IO devices. This
behaviour can be enabled with:
  cpu_lm32_set_phys_msb_ignore(env, 1);