From ae705387a968baf6ba36e887977c387b35fbec25 Mon Sep 17 00:00:00 2001 From: Alyssa Rosenzweig Date: Sat, 18 May 2019 20:48:43 +0000 Subject: panfrost/decode: Decode blend constant This adds a forgotten decode line on Midgard and adds the field of a blend constant on Bifrost. The Bifrost encoding is fairly weird; whereas Midgard is just a regular 32-bit float, Bifrost uses a fancy fixed-point-esque encoding. The decode logic here is experimentally correct. The encode logic is a sort of "guesstimate", assuming that the high byte is just int(f / 255.0) and then solving algebraicly for the low byte. This might be slightly off in some cases. Signed-off-by: Alyssa Rosenzweig Reviewed-by: Ryan Houdek --- src/gallium/drivers/panfrost/include/panfrost-job.h | 16 +++++++++++++++- src/gallium/drivers/panfrost/pandecode/decode.c | 17 ++++++++++++++++- 2 files changed, 31 insertions(+), 2 deletions(-) (limited to 'src/gallium/drivers') diff --git a/src/gallium/drivers/panfrost/include/panfrost-job.h b/src/gallium/drivers/panfrost/include/panfrost-job.h index fb4a12fe156..48b3a65a0b8 100644 --- a/src/gallium/drivers/panfrost/include/panfrost-job.h +++ b/src/gallium/drivers/panfrost/include/panfrost-job.h @@ -442,7 +442,21 @@ struct bifrost_blend_rt { /* This is likely an analogue of the flags on * midgard_blend_rt */ - u32 unk1; // = 0x200 + u16 flags; // = 0x200 + + /* Single-channel blend constants are encoded in a sort of + * fixed-point. Basically, the float is mapped to a byte, becoming + * a high byte, and then the lower-byte is added for precision. + * For the original float f: + * + * f = (constant_hi / 255) + (constant_lo / 65535) + * + * constant_hi = int(f / 255) + * constant_lo = 65535*f - (65535/255) * constant_hi + */ + + u16 constant; + struct mali_blend_equation equation; /* * - 0x19 normally diff --git a/src/gallium/drivers/panfrost/pandecode/decode.c b/src/gallium/drivers/panfrost/pandecode/decode.c index e70ebb7f660..fa91094d1f0 100644 --- a/src/gallium/drivers/panfrost/pandecode/decode.c +++ b/src/gallium/drivers/panfrost/pandecode/decode.c @@ -878,6 +878,17 @@ pandecode_replay_blend_equation(const struct mali_blend_equation *blend) pandecode_log("},\n"); } +/* Decodes a Bifrost blend constant. See the notes in bifrost_blend_rt */ + +static unsigned +decode_bifrost_constant(u16 constant) +{ + float lo = (float) (constant & 0xFF); + float hi = (float) (constant >> 8); + + return (hi / 255.0) + (lo / 65535.0); +} + static mali_ptr pandecode_bifrost_blend(void *descs, int job_no, int rt_no) { @@ -887,7 +898,10 @@ pandecode_bifrost_blend(void *descs, int job_no, int rt_no) pandecode_log("struct bifrost_blend_rt blend_rt_%d_%d = {\n", job_no, rt_no); pandecode_indent++; - pandecode_prop("unk1 = 0x%" PRIx32, b->unk1); + pandecode_prop("flags = 0x%" PRIx16, b->flags); + pandecode_prop("constant = 0x%" PRIx8 " /* %f */", + b->constant, decode_bifrost_constant(b->constant)); + /* TODO figure out blend shader enable bit */ pandecode_replay_blend_equation(&b->equation); pandecode_prop("unk2 = 0x%" PRIx16, b->unk2); @@ -910,6 +924,7 @@ pandecode_midgard_blend(union midgard_blend *blend, bool is_shader) pandecode_replay_shader_address("shader", blend->shader); } else { pandecode_replay_blend_equation(&blend->equation); + pandecode_prop("constant = %f", blend->constant); } pandecode_indent--; -- cgit v1.2.3