From 0ddf0f1c3451eef8a7c7f46afca623dc4f7c5af6 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Mon, 15 Aug 2011 21:02:10 -0700 Subject: [PATCH] i965/vs: Fix multiplies to actually do 32-bit multiplies. Fixes vs-op-mult-int-int and friends. --- src/mesa/drivers/dri/i965/brw_vec4_emit.cpp | 5 +++++ src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp | 18 +++++++++++++++++- 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp index fca31b6dec9..011af6f2d3e 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_emit.cpp @@ -633,6 +633,11 @@ vec4_visitor::generate_code() case BRW_OPCODE_MUL: brw_MUL(p, dst, src[0], src[1]); break; + case BRW_OPCODE_MACH: + brw_set_acc_write_control(p, 1); + brw_MACH(p, dst, src[0], src[1]); + brw_set_acc_write_control(p, 0); + break; case BRW_OPCODE_FRC: brw_FRC(p, dst, src[0]); diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp index 621cb53ff84..a60fc5f6ada 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp @@ -945,7 +945,23 @@ vec4_visitor::visit(ir_expression *ir) break; case ir_binop_mul: - emit(BRW_OPCODE_MUL, result_dst, op[0], op[1]); + if (ir->type->is_integer()) { + /* For integer multiplication, the MUL uses the low 16 bits + * of one of the operands (src0 on gen6, src1 on gen7). The + * MACH accumulates in the contribution of the upper 16 bits + * of that operand. + * + * FINISHME: Emit just the MUL if we know an operand is small + * enough. + */ + struct brw_reg acc = retype(brw_acc_reg(), BRW_REGISTER_TYPE_D); + + emit(BRW_OPCODE_MUL, acc, op[0], op[1]); + emit(BRW_OPCODE_MACH, dst_null_d(), op[0], op[1]); + emit(BRW_OPCODE_MOV, result_dst, src_reg(acc)); + } else { + emit(BRW_OPCODE_MUL, result_dst, op[0], op[1]); + } break; case ir_binop_div: assert(!"not reached: should be handled by ir_div_to_mul_rcp"); -- 2.30.2