diff options
| author | Cédric Le Goater <clg@kaod.org> | 2021-09-20 08:12:03 +0200 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2021-09-30 12:26:06 +1000 |
| commit | 4d9b8ef9b5ab880d491b0c41d222b42ed83bdbfe (patch) | |
| tree | 201bec0192a3ac479d416a4dccad08bd196afe3b /hw/ppc/ppc.c | |
| parent | af96d2e69227fc25f663d840527dbe2a0c592400 (diff) | |
target/ppc: Fix 64-bit decrementer
The current way the mask is built can overflow with a 64-bit decrementer.
Use sextract64() to extract the signed values and remove the logic to
handle negative values which has become useless.
Cc: Luis Fernando Fujita Pires <luis.pires@eldorado.org.br>
Fixes: a8dafa525181 ("target/ppc: Implement large decrementer support for TCG")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20210920061203.989563-5-clg@kaod.org>
Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'hw/ppc/ppc.c')
| -rw-r--r-- | hw/ppc/ppc.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/hw/ppc/ppc.c b/hw/ppc/ppc.c index b813ef732e..f5d012f860 100644 --- a/hw/ppc/ppc.c +++ b/hw/ppc/ppc.c @@ -821,14 +821,12 @@ static void __cpu_ppc_store_decr(PowerPCCPU *cpu, uint64_t *nextp, CPUPPCState *env = &cpu->env; ppc_tb_t *tb_env = env->tb_env; uint64_t now, next; - bool negative; + int64_t signed_value; + int64_t signed_decr; /* Truncate value to decr_width and sign extend for simplicity */ - value &= ((1ULL << nr_bits) - 1); - negative = !!(value & (1ULL << (nr_bits - 1))); - if (negative) { - value |= (0xFFFFFFFFULL << nr_bits); - } + signed_value = sextract64(value, 0, nr_bits); + signed_decr = sextract64(decr, 0, nr_bits); trace_ppc_decr_store(nr_bits, decr, value); @@ -850,16 +848,16 @@ static void __cpu_ppc_store_decr(PowerPCCPU *cpu, uint64_t *nextp, * On MSB edge based DEC implementations the MSB going from 0 -> 1 triggers * an edge interrupt, so raise it here too. */ - if ((value < 3) || - ((tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL) && negative) || - ((tb_env->flags & PPC_DECR_UNDERFLOW_TRIGGERED) && negative - && !(decr & (1ULL << (nr_bits - 1))))) { + if ((signed_value < 3) || + ((tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL) && signed_value < 0) || + ((tb_env->flags & PPC_DECR_UNDERFLOW_TRIGGERED) && signed_value < 0 + && signed_decr >= 0)) { (*raise_excp)(cpu); return; } /* On MSB level based systems a 0 for the MSB stops interrupt delivery */ - if (!negative && (tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL)) { + if (signed_value >= 0 && (tb_env->flags & PPC_DECR_UNDERFLOW_LEVEL)) { (*lower_excp)(cpu); } |