From: lkcl <lkcl@web>
Date: Tue, 5 Oct 2021 19:29:38 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: opf_rfc_ls005_v1~3702
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=af6dc8c6e6c8b0376acec66833889f3a160257c7;p=libreriscv.git

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diff --git a/3d_gpu/architecture/dynamic_simd/repl.mdwn b/3d_gpu/architecture/dynamic_simd/repl.mdwn
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+# PartitionedSignal nmigen-aware Repl
+
+* <https://bugs.libre-soc.org/show_bug.cgi?id=458>
+
+Partitioned Repl is very similar to [[cat]] and
+[[assign]].  The output completely changes depending
+on the partition mask.
+
+Take a PartitionedSignal:
+
+    partition:      p    p    p       (3 bits)
+    a        :  AAA3 AAA2 AAA1 AAA0  (32 bits)
+
+When the partitions are 32-bit, the output is:
+
+    partition:           p         p         p           (3 bits)
+    out      :  AAA3 AAA2 AAA1 AAA0 BBB3 BBB2 BBB1 BBB0  (64 bits)
+
+When 2x16, the top 2 halves of A and B are Catted together,
+and likewise the lower:
+
+    partition:           p         p         p           (3 bits)
+    out      :  AAA3 AAA2 BBB3 BBB2 AAA1 AAA0 BBB1 BBB0  (64 bits)
+
+Finally when 4x8, each byte is concatenated:
+
+    partition:           p         p         p           (3 bits)
+    out      :  AAA3 BBB3 AAA2 BBB2 AAA1 BBB1 AAA0 BBB0  (64 bits)
+