target-arm: A64: implement FMOV

Implement FMOV, ie non-converting moves between general purpose
registers and floating point registers. This is a subtype of
the floating point <-> integer instruction class.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

target-arm/translate-a64.c

@@ -2758,6 +2758,63 @@ static void disas_fp_fixed_conv(DisasContext *s, uint32_t insn)
     unsupported_encoding(s, insn);
 }
 
+static void handle_fmov(DisasContext *s, int rd, int rn, int type, bool itof)
+{
+    /* FMOV: gpr to or from float, double, or top half of quad fp reg,
+     * without conversion.
+     */
+
+    if (itof) {
+        int freg_offs = offsetof(CPUARMState, vfp.regs[rd * 2]);
+        TCGv_i64 tcg_rn = cpu_reg(s, rn);
+
+        switch (type) {
+        case 0:
+        {
+            /* 32 bit */
+            TCGv_i64 tmp = tcg_temp_new_i64();
+            tcg_gen_ext32u_i64(tmp, tcg_rn);
+            tcg_gen_st_i64(tmp, cpu_env, freg_offs);
+            tcg_gen_movi_i64(tmp, 0);
+            tcg_gen_st_i64(tmp, cpu_env, freg_offs + sizeof(float64));
+            tcg_temp_free_i64(tmp);
+            break;
+        }
+        case 1:
+        {
+            /* 64 bit */
+            TCGv_i64 tmp = tcg_const_i64(0);
+            tcg_gen_st_i64(tcg_rn, cpu_env, freg_offs);
+            tcg_gen_st_i64(tmp, cpu_env, freg_offs + sizeof(float64));
+            tcg_temp_free_i64(tmp);
+            break;
+        }
+        case 2:
+            /* 64 bit to top half. */
+            tcg_gen_st_i64(tcg_rn, cpu_env, freg_offs + sizeof(float64));
+            break;
+        }
+    } else {
+        int freg_offs = offsetof(CPUARMState, vfp.regs[rn * 2]);
+        TCGv_i64 tcg_rd = cpu_reg(s, rd);
+
+        switch (type) {
+        case 0:
+            /* 32 bit */
+            tcg_gen_ld32u_i64(tcg_rd, cpu_env, freg_offs);
+            break;
+        case 2:
+            /* 64 bits from top half */
+            freg_offs += sizeof(float64);
+            /* fall through */
+        case 1:
+            /* 64 bit */
+            tcg_gen_ld_i64(tcg_rd, cpu_env, freg_offs);
+            break;
+        }
+    }
+}
+
 /* C3.6.30 Floating point <-> integer conversions
  *   31   30  29 28       24 23  22  21 20   19 18 16 15         10 9  5 4  0
  * +----+---+---+-----------+------+---+-------+-----+-------------+----+----+
@@ -2766,7 +2823,34 @@ static void disas_fp_fixed_conv(DisasContext *s, uint32_t insn)
  */
 static void disas_fp_int_conv(DisasContext *s, uint32_t insn)
 {
-    unsupported_encoding(s, insn);
+    int rd = extract32(insn, 0, 5);
+    int rn = extract32(insn, 5, 5);
+    int opcode = extract32(insn, 16, 3);
+    int rmode = extract32(insn, 19, 2);
+    int type = extract32(insn, 22, 2);
+    bool sbit = extract32(insn, 29, 1);
+    bool sf = extract32(insn, 31, 1);
+
+    if (!sbit && (rmode < 2) && (opcode > 5)) {
+        /* FMOV */
+        bool itof = opcode & 1;
+
+        switch (sf << 3 | type << 1 | rmode) {
+        case 0x0: /* 32 bit */
+        case 0xa: /* 64 bit */
+        case 0xd: /* 64 bit to top half of quad */
+            break;
+        default:
+            /* all other sf/type/rmode combinations are invalid */
+            unallocated_encoding(s);
+            break;
+        }
+
+        handle_fmov(s, rd, rn, type, itof);
+    } else {
+        /* actual FP conversions */
+        unsupported_encoding(s, insn);
+    }
 }
 
 /* FP-specific subcases of table C3-6 (SIMD and FP data processing)