From d848bf85368b571b603f52625b581dad529e5997 Mon Sep 17 00:00:00 2001 From: Luke Kenneth Casson Leighton Date: Sun, 3 May 2020 23:15:33 +0100 Subject: [PATCH] add FU-FU and FU-Regs vectors --- 3d_gpu/architecture/6600scoreboard.mdwn | 41 +++++++++++++++++- ...ng_vec.png => fu_regs_row_pending_vec.png} | Bin 2 files changed, 40 insertions(+), 1 deletion(-) rename 3d_gpu/{fu_fu_row_pending_vec.png => fu_regs_row_pending_vec.png} (100%) diff --git a/3d_gpu/architecture/6600scoreboard.mdwn b/3d_gpu/architecture/6600scoreboard.mdwn index f0076fa67..b2eca9442 100644 --- a/3d_gpu/architecture/6600scoreboard.mdwn +++ b/3d_gpu/architecture/6600scoreboard.mdwn @@ -594,7 +594,7 @@ so my questions are: [[!img dependence_cell_multi_pending.jpg size="600x"]] -# Corresponding Function-Unit Dependency Cell Modifications +# Corresponding FU-FU (Function-to-Function) Dependency Cell Modifications * Video @@ -606,3 +606,42 @@ Augmented multi-GORD/GOWR 6600 FU-FU Cell diagram: [[!img fu_dep_cell_multi_6600.jpg size="600x"]] +# FU-Regs Vectors + +There are two FU-Regs Vectors. The first is an accumulation of +all row information. This indicates that (on a per-Operand basis +in the Libre-SOC design) there is *a* write pending for that Operand +(note that this is not per **register**, it is per **operand**). +Likewise, the OR-accumulation of every unary-encoded register SR-Latch +bit in the row, for reading for each FU's Operand, indicates a +desire of that Function Unit's need to *read* from a given port. + +These accumulated signals, coming out on a per-row basis for each +Operand port, are sent straight to every cell in the corresponding +FU-FU Matrix row. + +[[!img fu_regs_row_pending.png size="600x"]] + +The second vector set accumulates the **column** information. With the +FU-Regs Cells capturing the instruction operand read/write register +numbers (in unary form), the ORing per column of those bits creates +a "global picture", per register, of the fact that *any* Function Unit +needs to read (or write) a particular Operand latch port. + +[[!img fu_regs_global_pending_vec.png size="500x"]] + +# FU-FU Vectors + +Two vectors exist that accumulate row and column information. With the +FU-FU Cell recording whether the Function Unit *wants* to read (or write) +the per-cell information is not so crucial as the *accumulation* of that +information. When all other Function Units in that column no longer +indicate that they were waiting for a read, that FU is clear to **write**. +Correspondingly, when all FUs in the column no longer indicate waiting +for a write, that FU is clear to **read**. With a full NxN matrix of +cells, this inversion preserves Read-after-Write and Write-after-Read +hazard information relationships between **all** Function Units and all +other Function Units. + +[[!img fu_fu_readable_writeable.png size="500x"]] + diff --git a/3d_gpu/fu_fu_row_pending_vec.png b/3d_gpu/fu_regs_row_pending_vec.png similarity index 100% rename from 3d_gpu/fu_fu_row_pending_vec.png rename to 3d_gpu/fu_regs_row_pending_vec.png -- 2.30.2