From 18821281d30bace08963763f00379b57bcdcdf07 Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Thu, 6 Dec 2018 18:18:18 +0000 Subject: [PATCH] add comments --- 3d_gpu/microarchitecture.mdwn | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/3d_gpu/microarchitecture.mdwn b/3d_gpu/microarchitecture.mdwn index 00b0ac970..04678c6e3 100644 --- a/3d_gpu/microarchitecture.mdwn +++ b/3d_gpu/microarchitecture.mdwn @@ -249,6 +249,20 @@ Video @ 3:24, "RAT" table - Register Aliasing Table: This scheme looks very much like a Reservation Station. +---- + +There is another way to get precise ordering of the writes in a scoreboard. +First, one has to implement forwarding in the scoreboard. +Second, the function units need an output queue +Now, one can launch an instruction and pick up its operand either +from the RF or from the function unit output while the result sits +in the function unit waiting for its GO_Write signal. + +Thus the launching of instructions is not delayed due to hazards +but the results are delivered to the RF in program order. + +This looks surprisingly like a 'belt' at the end of the function unit. + # References * -- 2.30.2