|
@@ -468,27 +468,42 @@ set_default_state(struct radeon_device *rdev)
|
|
|
radeon_ring_write(ring, sq_stack_resource_mgmt_2);
|
|
|
}
|
|
|
|
|
|
+#define I2F_MAX_BITS 15
|
|
|
+#define I2F_MAX_INPUT ((1 << I2F_MAX_BITS) - 1)
|
|
|
+#define I2F_SHIFT (24 - I2F_MAX_BITS)
|
|
|
+
|
|
|
+/*
|
|
|
+ * Converts unsigned integer into 32-bit IEEE floating point representation.
|
|
|
+ * Conversion is not universal and only works for the range from 0
|
|
|
+ * to 2^I2F_MAX_BITS-1. Currently we only use it with inputs between
|
|
|
+ * 0 and 16384 (inclusive), so I2F_MAX_BITS=15 is enough. If necessary,
|
|
|
+ * I2F_MAX_BITS can be increased, but that will add to the loop iterations
|
|
|
+ * and slow us down. Conversion is done by shifting the input and counting
|
|
|
+ * down until the first 1 reaches bit position 23. The resulting counter
|
|
|
+ * and the shifted input are, respectively, the exponent and the fraction.
|
|
|
+ * The sign is always zero.
|
|
|
+ */
|
|
|
static uint32_t i2f(uint32_t input)
|
|
|
{
|
|
|
u32 result, i, exponent, fraction;
|
|
|
|
|
|
- if ((input & 0x3fff) == 0)
|
|
|
- result = 0; /* 0 is a special case */
|
|
|
+ WARN_ON_ONCE(input > I2F_MAX_INPUT);
|
|
|
+
|
|
|
+ if ((input & I2F_MAX_INPUT) == 0)
|
|
|
+ result = 0;
|
|
|
else {
|
|
|
- exponent = 140; /* exponent biased by 127; */
|
|
|
- fraction = (input & 0x3fff) << 10; /* cheat and only
|
|
|
- handle numbers below 2^^15 */
|
|
|
- for (i = 0; i < 14; i++) {
|
|
|
+ exponent = 126 + I2F_MAX_BITS;
|
|
|
+ fraction = (input & I2F_MAX_INPUT) << I2F_SHIFT;
|
|
|
+
|
|
|
+ for (i = 0; i < I2F_MAX_BITS; i++) {
|
|
|
if (fraction & 0x800000)
|
|
|
break;
|
|
|
else {
|
|
|
- fraction = fraction << 1; /* keep
|
|
|
- shifting left until top bit = 1 */
|
|
|
+ fraction = fraction << 1;
|
|
|
exponent = exponent - 1;
|
|
|
}
|
|
|
}
|
|
|
- result = exponent << 23 | (fraction & 0x7fffff); /* mask
|
|
|
- off top bit; assumed 1 */
|
|
|
+ result = exponent << 23 | (fraction & 0x7fffff);
|
|
|
}
|
|
|
return result;
|
|
|
}
|