diff options
| author | Nathan Froyd <froydnj@codesourcery.com> | 2010-06-08 13:30:01 -0700 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2010-06-09 16:10:51 +0200 |
| commit | bbfa8f72e99baa0514b2b39e671830cf9a3adc44 (patch) | |
| tree | 29d718f8b97573eb4b4b359e352159d696c0a19f | |
| parent | 3c824109da076d2a1df4b798f9df81b385131f92 (diff) | |
target-mips: add microMIPS exception handler support
Unlike MIPS16, microMIPS lets you choose the ISA mode for your exception
handlers. The ISA mode is selectable via a user-writable CP0.Config3
flag.
Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
| -rw-r--r-- | target-mips/cpu.h | 1 | ||||
| -rw-r--r-- | target-mips/helper.c | 21 |
2 files changed, 16 insertions, 6 deletions
diff --git a/target-mips/cpu.h b/target-mips/cpu.h index 7285636b68..c21b8e43ff 100644 --- a/target-mips/cpu.h +++ b/target-mips/cpu.h @@ -363,6 +363,7 @@ struct CPUMIPSState { #define CP0C2_SA 0 int32_t CP0_Config3; #define CP0C3_M 31 +#define CP0C3_ISA_ON_EXC 16 #define CP0C3_DSPP 10 #define CP0C3_LPA 7 #define CP0C3_VEIC 6 diff --git a/target-mips/helper.c b/target-mips/helper.c index 8102f03c26..ea221ab53f 100644 --- a/target-mips/helper.c +++ b/target-mips/helper.c @@ -385,6 +385,18 @@ static target_ulong exception_resume_pc (CPUState *env) return bad_pc; } + +static void set_hflags_for_handler (CPUState *env) +{ + /* Exception handlers are entered in 32-bit mode. */ + env->hflags &= ~(MIPS_HFLAG_M16); + /* ...except that microMIPS lets you choose. */ + if (env->insn_flags & ASE_MICROMIPS) { + env->hflags |= (!!(env->CP0_Config3 + & (1 << CP0C3_ISA_ON_EXC)) + << MIPS_HFLAG_M16_SHIFT); + } +} #endif void do_interrupt (CPUState *env) @@ -440,8 +452,7 @@ void do_interrupt (CPUState *env) if (!(env->CP0_Status & (1 << CP0St_EXL))) env->CP0_Cause &= ~(1 << CP0Ca_BD); env->active_tc.PC = (int32_t)0xBFC00480; - /* Exception handlers are entered in 32-bit mode. */ - env->hflags &= ~(MIPS_HFLAG_M16); + set_hflags_for_handler(env); break; case EXCP_RESET: cpu_reset(env); @@ -461,8 +472,7 @@ void do_interrupt (CPUState *env) if (!(env->CP0_Status & (1 << CP0St_EXL))) env->CP0_Cause &= ~(1 << CP0Ca_BD); env->active_tc.PC = (int32_t)0xBFC00000; - /* Exception handlers are entered in 32-bit mode. */ - env->hflags &= ~(MIPS_HFLAG_M16); + set_hflags_for_handler(env); break; case EXCP_EXT_INTERRUPT: cause = 0; @@ -581,8 +591,7 @@ void do_interrupt (CPUState *env) env->active_tc.PC = (int32_t)(env->CP0_EBase & ~0x3ff); } env->active_tc.PC += offset; - /* Exception handlers are entered in 32-bit mode. */ - env->hflags &= ~(MIPS_HFLAG_M16); + set_hflags_for_handler(env); env->CP0_Cause = (env->CP0_Cause & ~(0x1f << CP0Ca_EC)) | (cause << CP0Ca_EC); break; default: |