- return qir_MOV(c, qir_SEL(c, QPU_COND_NS,
- qir_FADD(c, trunc, qir_uniform_f(c, 1.0)),
- trunc));
+ return qir_MOV(c, result);
+}
+
+static struct qreg
+ntq_shrink_sincos_input_range(struct vc4_compile *c, struct qreg x)
+{
+ /* Since we're using a Taylor approximation, we want to have a small
+ * number of coefficients and take advantage of sin/cos repeating
+ * every 2pi. We keep our x as close to 0 as we can, since the series
+ * will be less accurate as |x| increases. (Also, be careful of
+ * shifting the input x value to be tricky with sin/cos relations,
+ * because getting accurate values for x==0 is very important for SDL
+ * rendering)
+ */
+ struct qreg scaled_x =
+ qir_FMUL(c, x,
+ qir_uniform_f(c, 1.0f / (M_PI * 2.0f)));
+ /* Note: FTOI truncates toward 0. */
+ struct qreg x_frac = qir_FSUB(c, scaled_x,
+ qir_ITOF(c, qir_FTOI(c, scaled_x)));
+ /* Map [0.5, 1] to [-0.5, 0] */
+ qir_SF(c, qir_FSUB(c, x_frac, qir_uniform_f(c, 0.5)));
+ qir_FSUB_dest(c, x_frac, x_frac, qir_uniform_f(c, 1.0))->cond = QPU_COND_NC;
+ /* Map [-1, -0.5] to [0, 0.5] */
+ qir_SF(c, qir_FADD(c, x_frac, qir_uniform_f(c, 0.5)));
+ qir_FADD_dest(c, x_frac, x_frac, qir_uniform_f(c, 1.0))->cond = QPU_COND_NS;
+
+ return x_frac;