<div dir="ltr"> <div class="gmail_extra"> <div class="gmail_quote">On Fri, Mar 25, 2016 at 4:12 PM, Jason Ekstrand <<a href="mailto:jason@jlekstrand.net" target="_blank">jason@jlekstrand.net</a>> wrote: <blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">--- src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 32 ++++++++++++++++++++++++++++++ src/mesa/drivers/dri/i965/brw_vec4_nir.cpp | 32 ++++++++++++++++++++++++++++++ 2 files changed, 64 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp index 14480fb..131f50e 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp @@ -844,8 +844,40 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr) unreachable("Should have been lowered by borrow_to_arith()."); case nir_op_umod: + case nir_op_irem: + /* According to the sign table for INT DIV in the Ivy Bridge PRM, it + * appears that our hardware just does the right thing for signed + * remainder. + */ + bld.emit(SHADER_OPCODE_INT_REMAINDER, result, op[0], op[1]); + break; + + case nir_op_imod: { + /* Get a regular C-style remainder. If a % b == 0, set the predicate. */ bld.emit(SHADER_OPCODE_INT_REMAINDER, result, op[0], op[1]); + + /* Math instructions don't support conditional mod */ + inst = bld.MOV(bld.null_reg_d(), result); + inst->conditional_mod = BRW_CONDITIONAL_NZ; + + /* Now, we need to determine if signs of the sources are different. + * When we XOR the sources, the top bit is 0 if they are the same and 1 + * if they are different. We can then use a conditional modifier to + * turn that into a predicate. This leads us to an XOR.l instruction. </blockquote><div> </div><div>I've added the following to this comment in both versions: * Technically, according to the PRM, you're not allowed to use .l on a * XOR instruction. However, emperical experiments and Curro's reading * of the simulator source both indicate that it's safe. </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + */ + fs_reg tmp = bld.vgrf(BRW_REGISTER_TYPE_D); + inst = bld.XOR(tmp, op[0], op[1]); + inst->predicate = BRW_PREDICATE_NORMAL; + inst->conditional_mod = BRW_CONDITIONAL_L; + + /* If the result of the initial remainder operation is non-zero and the + * two sources have different signs, add in a copy of op[1] to get the + * final integer modulus value. + */ + inst = bld.ADD(result, result, op[1]); + inst->predicate = BRW_PREDICATE_NORMAL; break; + } case nir_op_flt: case nir_op_ilt: diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp index 585674f..c18694f 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp @@ -1109,9 +1109,41 @@ vec4_visitor::nir_emit_alu(nir_alu_instr *instr) break; case nir_op_umod: + case nir_op_irem: + /* According to the sign table for INT DIV in the Ivy Bridge PRM, it + * appears that our hardware just does the right thing for signed + * remainder. + */ emit_math(SHADER_OPCODE_INT_REMAINDER, dst, op[0], op[1]); break; + case nir_op_imod: { + /* Get a regular C-style remainder. If a % b == 0, set the predicate. */ + inst = emit_math(SHADER_OPCODE_INT_REMAINDER, dst, op[0], op[1]); + + /* Math instructions don't support conditional mod */ + inst = emit(MOV(dst_null_d(), src_reg(dst))); + inst->conditional_mod = BRW_CONDITIONAL_NZ; + + /* Now, we need to determine if signs of the sources are different. + * When we XOR the sources, the top bit is 0 if they are the same and 1 + * if they are different. We can then use a conditional modifier to + * turn that into a predicate. This leads us to an XOR.l instruction. + */ + src_reg tmp = src_reg(this, glsl_type::ivec4_type); + inst = emit(XOR(dst_reg(tmp), op[0], op[1])); + inst->predicate = BRW_PREDICATE_NORMAL; + inst->conditional_mod = BRW_CONDITIONAL_L; + + /* If the result of the initial remainder operation is non-zero and the + * two sources have different signs, add in a copy of op[1] to get the + * final integer modulus value. + */ + inst = emit(ADD(dst, src_reg(dst), op[1])); + inst->predicate = BRW_PREDICATE_NORMAL; + break; + } + case nir_op_ldexp: unreachable("not reached: should be handled by ldexp_to_arith()"); -- 2.5.0.400.gff86faf </blockquote></div> </div></div>