emit_insn (gen_move_doubleword_fprdf (dest, src));
else if (!TARGET_64BIT && GET_MODE (dest) == V2SFmode)
emit_insn (gen_move_doubleword_fprv2sf (dest, src));
+ else if (!TARGET_64BIT && GET_MODE (dest) == V2SImode)
+ emit_insn (gen_move_doubleword_fprv2si (dest, src));
+ else if (!TARGET_64BIT && GET_MODE (dest) == V4HImode)
+ emit_insn (gen_move_doubleword_fprv4hi (dest, src));
+ else if (!TARGET_64BIT && GET_MODE (dest) == V8QImode)
+ emit_insn (gen_move_doubleword_fprv8qi (dest, src));
else if (TARGET_64BIT && GET_MODE (dest) == TFmode)
emit_insn (gen_move_doubleword_fprtf (dest, src));
else
if (mode == TFmode && ISA_HAS_8CC)
return true;
+ /* Allow 64-bit vector modes for Loongson-2E/2F. */
+ if (TARGET_LOONGSON_VECTORS
+ && (mode == V2SImode
+ || mode == V4HImode
+ || mode == V8QImode
+ || mode == DImode))
+ return true;
+
if (class == MODE_FLOAT
|| class == MODE_COMPLEX_FLOAT
|| class == MODE_VECTOR_FLOAT)
case V4UQQmode:
return TARGET_DSP;
+ case V2SImode:
+ case V4HImode:
+ case V8QImode:
+ return TARGET_LOONGSON_VECTORS;
+
default:
return false;
}
AVAIL_NON_MIPS16 (dspr2, TARGET_DSPR2)
AVAIL_NON_MIPS16 (dsp_32, !TARGET_64BIT && TARGET_DSP)
AVAIL_NON_MIPS16 (dspr2_32, !TARGET_64BIT && TARGET_DSPR2)
+AVAIL_NON_MIPS16 (loongson, TARGET_LOONGSON_VECTORS)
/* Construct a mips_builtin_description from the given arguments.
MIPS_BUILTIN (bposge, f, "bposge" #VALUE, \
MIPS_BUILTIN_BPOSGE ## VALUE, MIPS_SI_FTYPE_VOID, AVAIL)
+/* Define a Loongson MIPS_BUILTIN_DIRECT function __builtin_loongson_<FN_NAME>
+ for instruction CODE_FOR_loongson_<INSN>. FUNCTION_TYPE is a
+ builtin_description field. */
+#define LOONGSON_BUILTIN_ALIAS(INSN, FN_NAME, FUNCTION_TYPE) \
+ { CODE_FOR_loongson_ ## INSN, 0, "__builtin_loongson_" #FN_NAME, \
+ MIPS_BUILTIN_DIRECT, FUNCTION_TYPE, mips_builtin_avail_loongson }
+
+/* Define a Loongson MIPS_BUILTIN_DIRECT function __builtin_loongson_<INSN>
+ for instruction CODE_FOR_loongson_<INSN>. FUNCTION_TYPE is a
+ builtin_description field. */
+#define LOONGSON_BUILTIN(INSN, FUNCTION_TYPE) \
+ LOONGSON_BUILTIN_ALIAS (INSN, INSN, FUNCTION_TYPE)
+
+/* Like LOONGSON_BUILTIN, but add _<SUFFIX> to the end of the function name.
+ We use functions of this form when the same insn can be usefully applied
+ to more than one datatype. */
+#define LOONGSON_BUILTIN_SUFFIX(INSN, SUFFIX, FUNCTION_TYPE) \
+ LOONGSON_BUILTIN_ALIAS (INSN, INSN ## _ ## SUFFIX, FUNCTION_TYPE)
+
#define CODE_FOR_mips_sqrt_ps CODE_FOR_sqrtv2sf2
#define CODE_FOR_mips_addq_ph CODE_FOR_addv2hi3
#define CODE_FOR_mips_addu_qb CODE_FOR_addv4qi3
#define CODE_FOR_mips_subu_qb CODE_FOR_subv4qi3
#define CODE_FOR_mips_mul_ph CODE_FOR_mulv2hi3
+#define CODE_FOR_loongson_packsswh CODE_FOR_vec_pack_ssat_v2si
+#define CODE_FOR_loongson_packsshb CODE_FOR_vec_pack_ssat_v4hi
+#define CODE_FOR_loongson_packushb CODE_FOR_vec_pack_usat_v4hi
+#define CODE_FOR_loongson_paddw CODE_FOR_addv2si3
+#define CODE_FOR_loongson_paddh CODE_FOR_addv4hi3
+#define CODE_FOR_loongson_paddb CODE_FOR_addv8qi3
+#define CODE_FOR_loongson_paddsh CODE_FOR_ssaddv4hi3
+#define CODE_FOR_loongson_paddsb CODE_FOR_ssaddv8qi3
+#define CODE_FOR_loongson_paddush CODE_FOR_usaddv4hi3
+#define CODE_FOR_loongson_paddusb CODE_FOR_usaddv8qi3
+#define CODE_FOR_loongson_pmaxsh CODE_FOR_smaxv4hi3
+#define CODE_FOR_loongson_pmaxub CODE_FOR_umaxv8qi3
+#define CODE_FOR_loongson_pminsh CODE_FOR_sminv4hi3
+#define CODE_FOR_loongson_pminub CODE_FOR_uminv8qi3
+#define CODE_FOR_loongson_pmulhuh CODE_FOR_umulv4hi3_highpart
+#define CODE_FOR_loongson_pmulhh CODE_FOR_smulv4hi3_highpart
+#define CODE_FOR_loongson_biadd CODE_FOR_reduc_uplus_v8qi
+#define CODE_FOR_loongson_psubw CODE_FOR_subv2si3
+#define CODE_FOR_loongson_psubh CODE_FOR_subv4hi3
+#define CODE_FOR_loongson_psubb CODE_FOR_subv8qi3
+#define CODE_FOR_loongson_psubsh CODE_FOR_sssubv4hi3
+#define CODE_FOR_loongson_psubsb CODE_FOR_sssubv8qi3
+#define CODE_FOR_loongson_psubush CODE_FOR_ussubv4hi3
+#define CODE_FOR_loongson_psubusb CODE_FOR_ussubv8qi3
+#define CODE_FOR_loongson_punpckhbh CODE_FOR_vec_interleave_highv8qi
+#define CODE_FOR_loongson_punpckhhw CODE_FOR_vec_interleave_highv4hi
+#define CODE_FOR_loongson_punpckhwd CODE_FOR_vec_interleave_highv2si
+#define CODE_FOR_loongson_punpcklbh CODE_FOR_vec_interleave_lowv8qi
+#define CODE_FOR_loongson_punpcklhw CODE_FOR_vec_interleave_lowv4hi
+#define CODE_FOR_loongson_punpcklwd CODE_FOR_vec_interleave_lowv2si
+
static const struct mips_builtin_description mips_builtins[] = {
DIRECT_BUILTIN (pll_ps, MIPS_V2SF_FTYPE_V2SF_V2SF, paired_single),
DIRECT_BUILTIN (pul_ps, MIPS_V2SF_FTYPE_V2SF_V2SF, paired_single),
DIRECT_BUILTIN (dpaqx_s_w_ph, MIPS_DI_FTYPE_DI_V2HI_V2HI, dspr2_32),
DIRECT_BUILTIN (dpaqx_sa_w_ph, MIPS_DI_FTYPE_DI_V2HI_V2HI, dspr2_32),
DIRECT_BUILTIN (dpsqx_s_w_ph, MIPS_DI_FTYPE_DI_V2HI_V2HI, dspr2_32),
- DIRECT_BUILTIN (dpsqx_sa_w_ph, MIPS_DI_FTYPE_DI_V2HI_V2HI, dspr2_32)
+ DIRECT_BUILTIN (dpsqx_sa_w_ph, MIPS_DI_FTYPE_DI_V2HI_V2HI, dspr2_32),
+
+ /* Builtin functions for ST Microelectronics Loongson-2E/2F cores. */
+ LOONGSON_BUILTIN (packsswh, MIPS_V4HI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN (packsshb, MIPS_V8QI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (packushb, MIPS_UV8QI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (paddw, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (paddh, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (paddb, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (paddw, s, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_SUFFIX (paddh, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (paddb, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (paddd, u, MIPS_UDI_FTYPE_UDI_UDI),
+ LOONGSON_BUILTIN_SUFFIX (paddd, s, MIPS_DI_FTYPE_DI_DI),
+ LOONGSON_BUILTIN (paddsh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (paddsb, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN (paddush, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN (paddusb, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_ALIAS (pandn_d, pandn_ud, MIPS_UDI_FTYPE_UDI_UDI),
+ LOONGSON_BUILTIN_ALIAS (pandn_w, pandn_uw, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_ALIAS (pandn_h, pandn_uh, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_ALIAS (pandn_b, pandn_ub, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_ALIAS (pandn_d, pandn_sd, MIPS_DI_FTYPE_DI_DI),
+ LOONGSON_BUILTIN_ALIAS (pandn_w, pandn_sw, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_ALIAS (pandn_h, pandn_sh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_ALIAS (pandn_b, pandn_sb, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN (pavgh, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN (pavgb, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqw, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqh, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqb, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqw, s, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqh, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpeqb, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgtw, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgth, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgtb, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgtw, s, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgth, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (pcmpgtb, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (pextrh, u, MIPS_UV4HI_FTYPE_UV4HI_USI),
+ LOONGSON_BUILTIN_SUFFIX (pextrh, s, MIPS_V4HI_FTYPE_V4HI_USI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_0, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_1, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_2, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_3, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_0, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_1, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_2, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (pinsrh_3, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pmaddhw, MIPS_V2SI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pmaxsh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pmaxub, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN (pminsh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pminub, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pmovmskb, u, MIPS_UV8QI_FTYPE_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pmovmskb, s, MIPS_V8QI_FTYPE_V8QI),
+ LOONGSON_BUILTIN (pmulhuh, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN (pmulhh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pmullh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (pmuluw, MIPS_UDI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN (pasubub, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN (biadd, MIPS_UV4HI_FTYPE_UV8QI),
+ LOONGSON_BUILTIN (psadbh, MIPS_UV4HI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (pshufh, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (pshufh, s, MIPS_V4HI_FTYPE_V4HI_V4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psllh, u, MIPS_UV4HI_FTYPE_UV4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psllh, s, MIPS_V4HI_FTYPE_V4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psllw, u, MIPS_UV2SI_FTYPE_UV2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psllw, s, MIPS_V2SI_FTYPE_V2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrah, u, MIPS_UV4HI_FTYPE_UV4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrah, s, MIPS_V4HI_FTYPE_V4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psraw, u, MIPS_UV2SI_FTYPE_UV2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psraw, s, MIPS_V2SI_FTYPE_V2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrlh, u, MIPS_UV4HI_FTYPE_UV4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrlh, s, MIPS_V4HI_FTYPE_V4HI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrlw, u, MIPS_UV2SI_FTYPE_UV2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psrlw, s, MIPS_V2SI_FTYPE_V2SI_UQI),
+ LOONGSON_BUILTIN_SUFFIX (psubw, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (psubh, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (psubb, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (psubw, s, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_SUFFIX (psubh, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (psubb, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (psubd, u, MIPS_UDI_FTYPE_UDI_UDI),
+ LOONGSON_BUILTIN_SUFFIX (psubd, s, MIPS_DI_FTYPE_DI_DI),
+ LOONGSON_BUILTIN (psubsh, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN (psubsb, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN (psubush, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN (psubusb, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhbh, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhhw, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhwd, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhbh, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhhw, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (punpckhwd, s, MIPS_V2SI_FTYPE_V2SI_V2SI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklbh, u, MIPS_UV8QI_FTYPE_UV8QI_UV8QI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklhw, u, MIPS_UV4HI_FTYPE_UV4HI_UV4HI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklwd, u, MIPS_UV2SI_FTYPE_UV2SI_UV2SI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklbh, s, MIPS_V8QI_FTYPE_V8QI_V8QI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklhw, s, MIPS_V4HI_FTYPE_V4HI_V4HI),
+ LOONGSON_BUILTIN_SUFFIX (punpcklwd, s, MIPS_V2SI_FTYPE_V2SI_V2SI)
};
/* MODE is a vector mode whose elements have type TYPE. Return the type
static tree
mips_builtin_vector_type (tree type, enum machine_mode mode)
{
- static tree types[(int) MAX_MACHINE_MODE];
+ static tree types[2 * (int) MAX_MACHINE_MODE];
+ int mode_index;
- if (types[(int) mode] == NULL_TREE)
- types[(int) mode] = build_vector_type_for_mode (type, mode);
- return types[(int) mode];
+ mode_index = (int) mode;
+
+ if (TREE_CODE (type) == INTEGER_TYPE && TYPE_UNSIGNED (type))
+ mode_index += MAX_MACHINE_MODE;
+
+ if (types[mode_index] == NULL_TREE)
+ types[mode_index] = build_vector_type_for_mode (type, mode);
+ return types[mode_index];
}
/* Source-level argument types. */
#define MIPS_ATYPE_POINTER ptr_type_node
/* Standard mode-based argument types. */
+#define MIPS_ATYPE_UQI unsigned_intQI_type_node
#define MIPS_ATYPE_SI intSI_type_node
#define MIPS_ATYPE_USI unsigned_intSI_type_node
#define MIPS_ATYPE_DI intDI_type_node
+#define MIPS_ATYPE_UDI unsigned_intDI_type_node
#define MIPS_ATYPE_SF float_type_node
#define MIPS_ATYPE_DF double_type_node
/* Vector argument types. */
#define MIPS_ATYPE_V2SF mips_builtin_vector_type (float_type_node, V2SFmode)
#define MIPS_ATYPE_V2HI mips_builtin_vector_type (intHI_type_node, V2HImode)
+#define MIPS_ATYPE_V2SI mips_builtin_vector_type (intSI_type_node, V2SImode)
#define MIPS_ATYPE_V4QI mips_builtin_vector_type (intQI_type_node, V4QImode)
+#define MIPS_ATYPE_V4HI mips_builtin_vector_type (intHI_type_node, V4HImode)
+#define MIPS_ATYPE_V8QI mips_builtin_vector_type (intQI_type_node, V8QImode)
+#define MIPS_ATYPE_UV2SI \
+ mips_builtin_vector_type (unsigned_intSI_type_node, V2SImode)
+#define MIPS_ATYPE_UV4HI \
+ mips_builtin_vector_type (unsigned_intHI_type_node, V4HImode)
+#define MIPS_ATYPE_UV8QI \
+ mips_builtin_vector_type (unsigned_intQI_type_node, V8QImode)
/* MIPS_FTYPE_ATYPESN takes N MIPS_FTYPES-like type codes and lists
their associated MIPS_ATYPEs. */
}
}
+/* Initialize vector TARGET to VALS. */
+
+void
+mips_expand_vector_init (rtx target, rtx vals)
+{
+ enum machine_mode mode;
+ enum machine_mode inner;
+ unsigned int i, n_elts;
+ rtx mem;
+
+ mode = GET_MODE (target);
+ inner = GET_MODE_INNER (mode);
+ n_elts = GET_MODE_NUNITS (mode);
+
+ gcc_assert (VECTOR_MODE_P (mode));
+
+ mem = assign_stack_temp (mode, GET_MODE_SIZE (mode), 0);
+ for (i = 0; i < n_elts; i++)
+ emit_move_insn (adjust_address_nv (mem, inner, i * GET_MODE_SIZE (inner)),
+ XVECEXP (vals, 0, i));
+
+ emit_move_insn (target, mem);
+}
+
/* When generating MIPS16 code, we want to allocate $24 (T_REG) before
other registers for instructions for which it is possible. This
encourages the compiler to use CMP in cases where an XOR would