From: "Maciej W. Rozycki" <ma...@codesourcery.com>
Correct MIPS16/microMIPS branch size calculation in PC adjustment
needed:
- to set the value of CP0.ErrorEPC at the entry to the reset exception,
- for the purpose of branch reexecution in the context of device I/O.
Follow the approach taken in `exception_resume_pc' for ordinary, Debug
and NMI exceptions.
MIPS16 and microMIPS branches can be 2 or 4 bytes in size and that has
to be reflected in calculation. Original MIPS ISA branches, which is
where this code originates from, are always 4 bytes long, just as all
original MIPS ISA instructions.
Signed-off-by: Nathan Froyd <froy...@codesourcery.com>
Signed-off-by: Maciej W. Rozycki <ma...@codesourcery.com>
Reviewed-by: Leon Alrae <leon.al...@imgtec.com>
Signed-off-by: Leon Alrae <leon.al...@imgtec.com>
---
target-mips/translate.c | 3 ++-
translate-all.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/target-mips/translate.c b/target-mips/translate.c
index a5a5ca4..b5d5b39 100644
--- a/target-mips/translate.c
+++ b/target-mips/translate.c
@@ -19439,7 +19439,8 @@ void cpu_state_reset(CPUMIPSState *env)
if (env->hflags & MIPS_HFLAG_BMASK) {
/* If the exception was raised from a delay slot,
come back to the jump. */
- env->CP0_ErrorEPC = env->active_tc.PC - 4;
+ env->CP0_ErrorEPC = (env->active_tc.PC
+ - (env->hflags & MIPS_HFLAG_B16 ? 2 : 4));
} else {
env->CP0_ErrorEPC = env->active_tc.PC;
}
diff --git a/translate-all.c b/translate-all.c
index cf05472..d930a5c 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1540,7 +1540,7 @@ void cpu_io_recompile(CPUState *cpu, uintptr_t retaddr)
branch. */
#if defined(TARGET_MIPS)
if ((env->hflags & MIPS_HFLAG_BMASK) != 0 && n > 1) {
- env->active_tc.PC -= 4;
+ env->active_tc.PC -= (env->hflags & MIPS_HFLAG_B16 ? 2 : 4);
cpu->icount_decr.u16.low++;
env->hflags &= ~MIPS_HFLAG_BMASK;
}
--
2.1.0
