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PPC: Only set lower 32bits with mtmsr

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As Nathan pointed out correctly, the mtmsr instruction does not modify
the high 32 bits of MSR. It also doesn't matter if SF is set or not,
the instruction always behaves the same.

This patch moves it a bit closer to the spec.

Reported-by: Nathan Whitehorn <nwhitehorn@freebsd.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
Alexander Graf 2011-06-16 10:44:23 +02:00
parent a59106cbbb
commit 8018dc63aa
1 changed files with 6 additions and 11 deletions
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17
target-ppc/translate.c
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@ -3878,24 +3878,19 @@ static void gen_mtmsr(DisasContext *ctx)
tcg_gen_or_tl(cpu_msr, cpu_msr, t0);
tcg_temp_free(t0);
} else {
TCGv msr = tcg_temp_new();
/* XXX: we need to update nip before the store
* if we enter power saving mode, we will exit the loop
* directly from ppc_store_msr
*/
gen_update_nip(ctx, ctx->nip);
#if defined(TARGET_PPC64)
if (!ctx->sf_mode) {
TCGv t0 = tcg_temp_new();
TCGv t1 = tcg_temp_new();
tcg_gen_andi_tl(t0, cpu_msr, 0xFFFFFFFF00000000ULL);
tcg_gen_ext32u_tl(t1, cpu_gpr[rS(ctx->opcode)]);
tcg_gen_or_tl(t0, t0, t1);
tcg_temp_free(t1);
gen_helper_store_msr(t0);
tcg_temp_free(t0);
} else
tcg_gen_deposit_tl(msr, cpu_msr, cpu_gpr[rS(ctx->opcode)], 0, 32);
#else
tcg_gen_mov_tl(msr, cpu_gpr[rS(ctx->opcode)]);
#endif
gen_helper_store_msr(cpu_gpr[rS(ctx->opcode)]);
gen_helper_store_msr(msr);
/* Must stop the translation as machine state (may have) changed */
/* Note that mtmsr is not always defined as context-synchronizing */
gen_stop_exception(ctx);