AMD Publishes RDNA 2 ISA Documentation

[phoronix]

Phoronix: AMD Publishes RDNA 2 ISA Documentation

AMD has carried out a timely release of their RDNA 2 ISA documentation for those interested in working on any compiler support around these very latest graphics processors or working on other shader optimization approaches, etc...

http://www.phoronix.com/scan.php?page=news_item&px=AMD-RDNA2-ISA-Documentation

[Danny3]

Wonderful, good job AMD!

[Spacefish]

Wonder if RDNA2 ISA differs a lot from RDNA.. If not, that might be a good sign for ROCM support on RDNA based cards.

[bridgman]

Wonder if RDNA2 ISA differs a lot from RDNA.. If not, that might be a good sign for ROCM support on RDNA based cards.

We have a summary of changes between RDNA1 and RDNA2 at the start of the doc:

• Ray Tracing
• Dot product ALU operations added accelerate inferencing and deep-learning:

◦ V_DOT2_F32_F16 / V_DOT2C_F32_F16

◦ V_DOT2_I32_I16 / V_DOT2_U32_U16
◦ V_DOT4_I32_I8 / V_DOT4C_I32_I8
◦ V_DOT4_U32_U8
◦ V_DOT8_I32_I4
◦ V_DOT8_U32_U4

• Image Load MSAA
• Global memory loads with "Add-TID"
• Atomic clamped subtract buffer and global instructions
• VGPR & LDS allocation-unit size doubled
• S_MEMTIME replaced by "s_getreg_b32 Sn, SHADER_CYCLES"

Instruction Changes
Removed:

• V_MAC_LEGACY_F32 (replaced by V_FMAC_LEGACY_F32)
• V_MAD_LEGACY_F32 (replaced by V_FMA_LEGACY_F32)
• V_MAC_F32, V_MADMK_F32, V_MADAK_F32 (replaced by FMA equivalents)

Relatively small as generation-to-generation changes go.

Remember that we are already running OpenCL over the core ROCm stack on RDNA2 (and RDNA1 and Vega) today, starting with the 20.45 packaged driver release.

[geearf]

Thanks AMD!

[Go_Vulkan]

We have a summary of changes between

Hello Bridgman,
I wonder whether there is documentation about the VCN (Video Core Next) capabilities? Especially about new features of each VCN version? Also, which VCN generation is included in the different GPUs and APUs?

[bridgman]

I wonder whether there is documentation about the VCN (Video Core Next) capabilities? Especially about new features of each VCN version? Also, which VCN generation is included in the different GPUs and APUs?

We help to maintain some information on the X.org RadeonFeature page, but that's the only source I am aware of.

https://www.x.org/wiki/RadeonFeature/#radeonuvdunifiedvideodecoderhardware

We used to help maintain the Wikipedia pages as well but there are just too many different pages these days.

[baryluk]

Thanks AMD. Really appreciated.