target-mips: optimize mflo and mfhi

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6794 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
aurel32 2009-03-09 18:50:43 +00:00
parent 651721b2a5
commit a1f6684d65

View File

@ -1772,42 +1772,41 @@ static void gen_arith (CPUState *env, DisasContext *ctx, uint32_t opc,
static void gen_HILO (DisasContext *ctx, uint32_t opc, int reg)
{
const char *opn = "hilo";
TCGv t0 = tcg_temp_local_new();
if (reg == 0 && (opc == OPC_MFHI || opc == OPC_MFLO)) {
/* Treat as NOP. */
MIPS_DEBUG("NOP");
goto out;
return;
}
switch (opc) {
case OPC_MFHI:
tcg_gen_mov_tl(t0, cpu_HI[0]);
gen_store_gpr(t0, reg);
tcg_gen_mov_tl(cpu_gpr[reg], cpu_HI[0]);
opn = "mfhi";
break;
case OPC_MFLO:
tcg_gen_mov_tl(t0, cpu_LO[0]);
gen_store_gpr(t0, reg);
tcg_gen_mov_tl(cpu_gpr[reg], cpu_LO[0]);
opn = "mflo";
break;
case OPC_MTHI:
gen_load_gpr(t0, reg);
tcg_gen_mov_tl(cpu_HI[0], t0);
if (reg != 0)
tcg_gen_mov_tl(cpu_HI[0], cpu_gpr[reg]);
else
tcg_gen_movi_tl(cpu_HI[0], 0);
opn = "mthi";
break;
case OPC_MTLO:
gen_load_gpr(t0, reg);
tcg_gen_mov_tl(cpu_LO[0], t0);
if (reg != 0)
tcg_gen_mov_tl(cpu_LO[0], cpu_gpr[reg]);
else
tcg_gen_movi_tl(cpu_LO[0], 0);
opn = "mtlo";
break;
default:
MIPS_INVAL(opn);
generate_exception(ctx, EXCP_RI);
goto out;
return;
}
MIPS_DEBUG("%s %s", opn, regnames[reg]);
out:
tcg_temp_free(t0);
}
static void gen_muldiv (DisasContext *ctx, uint32_t opc,