target-mips: add Unified Hosting Interface (UHI) support

Add UHI semihosting support for MIPS. QEMU run with "-semihosting" option
will alter the behaviour of SDBBP 1 instruction -- UHI operation will be
called instead of generating a debug exception.

Also tweak Malta's pseudo-bootloader. On CPU reset the $4 register is set
to -1 if semihosting arguments are passed to indicate that the UHI
operations should be used to obtain input arguments.

Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Leon Alrae 2015-06-19 11:08:43 +01:00
parent ff33476772
commit 3b3c1694cf
6 changed files with 408 additions and 26 deletions

View file

@ -1,6 +1,8 @@
DEF_HELPER_3(raise_exception_err, noreturn, env, i32, int)
DEF_HELPER_2(raise_exception, noreturn, env, i32)
DEF_HELPER_1(do_semihosting, void, env)
#ifdef TARGET_MIPS64
DEF_HELPER_4(sdl, void, env, tl, tl, int)
DEF_HELPER_4(sdr, void, env, tl, tl, int)