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