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This is currently considered experimental, but most of the more commonly used instructions should work. So far only SI has been extensively tested, CI and VI probably work too, but may be buggy. The current set of tests cases do not give complete coverage, but I think it is sufficient for an experimental assembler. See the documentation in R600Usage for more information. llvm-svn: 234381
90 lines
2.3 KiB
ReStructuredText
90 lines
2.3 KiB
ReStructuredText
============================
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User Guide for R600 Back-end
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============================
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Introduction
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============
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The R600 back-end provides ISA code generation for AMD GPUs, starting with
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the R600 family up until the current Volcanic Islands (GCN Gen 3).
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Assembler
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=========
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The assembler is currently considered experimental.
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For syntax examples look in test/MC/R600.
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Below some of the currently supported features (modulo bugs). These
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all apply to the Southern Islands ISA, Sea Islands and Volcanic Islands
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are also supported but may be missing some instructions and have more bugs:
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DS Instructions
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---------------
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All DS instructions are supported.
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MUBUF Instructions
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------------------
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All non-atomic MUBUF instructions are supported.
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SMRD Instructions
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-----------------
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Only the s_load_dword* SMRD instructions are supported.
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SOP1 Instructions
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-----------------
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All SOP1 instructions are supported.
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SOP2 Instructions
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-----------------
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All SOP2 instructions are supported.
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SOPC Instructions
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-----------------
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All SOPC instructions are supported.
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SOPP Instructions
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-----------------
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Unless otherwise mentioned, all SOPP instructions that have one or more
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operands accept integer operands only. No verification is performed
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on the operands, so it is up to the programmer to be familiar with the
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range or acceptable values.
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s_waitcnt
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^^^^^^^^^
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s_waitcnt accepts named arguments to specify which memory counter(s) to
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wait for.
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.. code-block:: nasm
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// Wait for all counters to be 0
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s_waitcnt 0
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// Equivalent to s_waitcnt 0. Counter names can also be delimited by
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// '&' or ','.
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s_waitcnt vmcnt(0) expcnt(0) lgkcmt(0)
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// Wait for vmcnt counter to be 1.
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s_waitcnt vmcnt(1)
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VOP1, VOP2, VOP3, VOPC Instructions
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-----------------------------------
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All 32-bit and 64-bit encodings should work.
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The assembler will automatically detect which encoding size to use for
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VOP1, VOP2, and VOPC instructions based on the operands. If you want to force
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a specific encoding size, you can add an _e32 (for 32-bit encoding) or
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_e64 (for 64-bit encoding) suffix to the instruction. Most, but not all
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instructions support an explicit suffix. These are all valid assembly
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strings:
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.. code-block:: nasm
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v_mul_i32_i24 v1, v2, v3
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v_mul_i32_i24_e32 v1, v2, v3
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v_mul_i32_i24_e64 v1, v2, v3
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