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agx: Don't crash trying to encoding minifloats

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Fixes assertion fails in piglit isinf-and-isnan, which uses a constant infinity,
which has an out-of-bounds mantissa (but the function contract says that's
fine and we just return something undefined.)

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20563>
This commit is contained in:
Alyssa Rosenzweig
2023-01-05 20:52:09 -05:00
committed by Marge Bot
parent 7859b531c2
commit 4311c636c2
1 changed files with 5 additions and 7 deletions
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12
src/asahi/compiler/agx_minifloat.h
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@@ -45,9 +45,11 @@ agx_minifloat_decode(uint8_t imm)
}
/* Encodes a float. Results are only valid if the float can be represented
* exactly, if not the result of this function is UNDEFINED. signbit() is used
* to ensure -0.0 is handled correctly. */
* exactly, if not the result of this function is UNDEFINED. However, it is
* guaranteed that this function will not crash on out-of-spec inputs, so it is
* safe to call on any input. signbit() is used to ensure -0.0 is handled
* correctly.
*/
static inline uint8_t
agx_minifloat_encode(float f)
{
@@ -63,13 +65,9 @@ agx_minifloat_encode(float f)
exp -= 5; /* 2^5 = 32 */
exp = CLAMP(exp + 7, 0, 7);
assert(mantissa >= 0x10 && mantissa < 0x20);
assert(exp >= 1);
return sign | (exp << 4) | (mantissa & 0xF);
} else {
unsigned mantissa = (f * 64.0f);
assert(mantissa < 0x10);
return sign | mantissa;
}