make_ptx.py turns the 32 cvt.rn.f16x2.e4m3x2 of rrlite_dec0_4x4_folded into calls of d4r_dec_e4m3x2 (tex_common.h) when D4R_TEX_FP8=1: v_cvt_pk_f32_fp8 and two conversions to f16 instead of ZLUDA's integer lowering (about 25 instructions each; the kernel goes from 4058 to 3418 instructions). The conversion equals ZLUDA's e4m3_to_f16_bits for every code except the NaN codes 0x7f / 0xff, checked over all 65536 code pairs on an RX 9070 XT, and the head never stages those codes (it clamps to +-448 before encoding). Harness frames are byte-identical in the accuracy and the fast set, over a 16-frame moving sequence in the accuracy set. dec0 at 2227x1253 render: 0.43 -> 0.38 ms (accuracy), 0.36 -> 0.30 ms (fast). -DD4R_TEX_SOFT_E4M3 gives ZLUDA's lowering; builds without D4R_TEX_FP8 keep the PTX instruction.
On the gfx12 native-FP8 path the enc0 tail and the dec0 head encode their results with v_cvt_pk_fp8_f32 on the f32 copies of the f16 values (e4m3x4_f32 in tex_common.h) instead of ZLUDA's integer e4m3x2. The clamps keep the conversion in range: +-2pi for enc0 (the f16 bound hi[0], same in f32) and +-448 for dec0, both as a median of three, where a NaN gives the lower bound. The codes equal e4m3x2 for every non-NaN f16, checked over all 65536 patterns on an RX 9070 XT; a NaN in dec0 now encodes as -448 instead of the NaN code. Harness frames are byte-identical in both sets (LDR and HDR, motion vectors at render and display resolution). dec0: 0.21 -> 0.15 ms at 1280x720 render and 0.74 -> 0.53 ms at 2560x1440; enc0 changes by 1-2% (its time is ZLUDA's compile of the feature code). -DD4R_TEX_SOFT_E4M3 (D4R_TEX_CFLAGS) keeps e4m3x2.
The remaining two layers (96 channels, four heads) use the same swin_tok.h template: byte-identical on the same recorded launches and harness sequences, enc2 0.22 -> 0.14 ms and dec2 0.20 -> 0.14 ms at 1280x720 render, 0.75 -> 0.47 and 0.69 -> 0.47 ms at 2560x1440. Skipping windows that lie entirely outside the image is also exact but below the measurement noise (at most 2.4% of the windows of every other tube launch), so it is not kept; true16 code generation remains not tried.
swin_tok.h passes the weights as the first WMMA operand and the activations as the second, so each GEMM's encoded result is already the next one's operand and stays in registers (swin_block.h transposes every result through LDS). One wave owns one 4x4 window for the whole block: norms, attention and the MLP need no LDS and no barriers; only the patch expand and the patch merge go through an e4m3 image in LDS. Outputs are bit-identical to swin_block.h (swapped WMMA operand roles, verified on an RX 9070 XT and on recorded launches). mix2 rounds in place (accumulator is addend and destination, no copy per pair). -DSWIN_NO_TOKEN_LANES builds these layers from swin_block.h again; enc2 and dec2 are unchanged. RX 9070 XT accuracy set, 2560x1440 render: whole evaluation 8.56 -> 7.18 ms.
The 2x figure is against the previous native-FP8 layers. With NativeFp8 off
the RX 9070 XT was already at 3.37 ms for 1280x720 -> 3840x2160; the FP8 set
is 2.88 ms there.
The FP8 Swin layers encode with a clamp to +-448 (NaN-propagating packed
minimum/maximum) followed by v_cvt_pk_fp8_f32, in both the fast and the
accuracy build: equal to half_to_e4m3 for every non-NaN input, NaN encodes
as 0xff. The accuracy build rounds each k32 step with v_fma_mix (K32_MIX).
On gfx12 the accuracy builds of M's post and downsample kernels are wave64
with denormal handling kept.
RX 9070 XT, 1280x720 -> 3840x2160, D3D12 harness: the accuracy set goes
from 3.54 ms to 3.05 ms per evaluation (3.01 -> 2.59 ms under load). Its
Swin layers still equal swin_model.py on sampled blocks and its image is
byte-identical to the previous accuracy set over 8 temporal frames.
On the gfx12 native-FP8 path the Swin layers kept GEMM activations as f16
in LDS and encoded them to e4m3 again at every operand load. They are now
encoded once where they are produced, with v_cvt_pk_fp8_f32, and stored as
bytes (SWIN_A8); the patch merge reads the stored output codes. The M
downsample kernels are built as wave64 on gfx12.
RX 9070 XT, 1280x720 -> 3840x2160, D3D12 harness, DLSS 310.7: whole
evaluation 5.9 ms -> 2.8 ms of GPU time with the GPU otherwise idle, 2.4 ms
at 80-98% GPU utilisation. Harness output is byte-identical to the previous
kernels; the accuracy build matches swin_model.py on sampled blocks.
Builds without D4R_FP8_WMMA (RDNA3, and RDNA4 with NativeFp8 off) compile to
the same instructions as before.
woutermans