Re: [Qemu-devel] [PATCH v2 12/27] tcg-ppc64: Improve and_i32 with constant

[Richard Henderson <rth@twiddle.net>]

On 2013-04-01 07:55, Aurelien Jarno wrote:
>> >+static void tcg_out_andi32(TCGContext *s, TCGReg dst, TCGReg src, uint32_t c)
>> >+{
>> >+    int mb, me;
>> >+
>> >+    if ((c & 0xffff) == c) {
>> >+        tcg_out32(s, ANDI | SAI(src, dst, c));
>> >+        return;
>> >+    } else if ((c & 0xffff0000) == c) {
>> >+        tcg_out32(s, ANDIS | SAI(src, dst, c >> 16));
>> >+        return;
>> >+    } else if (mask_operand(c, &mb, &me)) {
>> >+        tcg_out_rlw(s, RLWINM, dst, src, 0, mb, me);
>> >+    } else {
>> >+        tcg_out_movi(s, TCG_TYPE_I32, 0, c);
>> >+        tcg_out32(s, AND | SAB(src, dst, 0));
> Give it's a 32-bit constant, wouldn't it be better to use ANDI +
> ANDIS here?
>

x & 0xffff0000 & 0x0000ffff == 0.

Unlike IOR and XOR...


r~