From c3577479815f5bcf9d38993967bca2115af245d8 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 7 Nov 2014 20:05:35 +0000 Subject: [PATCH] target-mips: Correct MIPS16/microMIPS branch size calculation 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 Signed-off-by: Maciej W. Rozycki Reviewed-by: Leon Alrae Signed-off-by: Leon Alrae --- 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 a5a5ca44ee..b5d5b39092 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 cf05472008..d930a5ce67 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; } -- 2.11.4.GIT