On 2013-05-27 04:43, Claudio Fontana wrote:
Hmm, true. Although I'd been thinking more along the lines of
arranging the code such that we'd use movz to set the zero.
I think we need to keep treating zero specially if we want to keep the
optimization where we don't emit needless MOVK instructions for half-words of
value 0000h.
I can however make one single function out of movi32 and movi64, it could look
like this:
if (!value) {
tcg_out_movr(s, 0, rd, TCG_REG_ZXR);
return;
}
base = (value > 0xffffffff) ? 0xd2800000 : 0x52800000;
while (value) {
/* etc etc */
}
if (type == TCG_TYPE_I32) {
value = (uint32_t)value;
ext = 0;
} else if (value <= 0xffffffff) {
ext = 0;
} else {
ext = 0x80000000;
}
base = 0x52800000; /* MOVZ */
do {
int shift = ctz64(value) & (63 & -16);
int half = (value >> shift) & 0xffff;
tcg_out32(s, base | ext | half << 5 | rd);
value &= ~(0xffffUL << shift);
base = 0x72800000; /* MOVK */
} while (value != 0);
Since we go through the loop at least once, we emit the movz for zero input.
No need for any extra tests. And using ctz we can iterate fewer times.
r~
