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authorRené Schümann <white06tiger@gmail.com>2015-03-14 19:56:55 +0000
committerRené Schümann <white06tiger@gmail.com>2015-03-14 19:56:55 +0000
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parentd2b26b1f86326362f56540b5185fa09ab5f2779c (diff)
MirOTR: part one of many file/folder structure changes
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+This directory contains mpn functions optimized for MIPS3. Example of
+processors that implement MIPS3 are R4000, R4400, R4600, R4700, and R8000.
+
+RELEVANT OPTIMIZATION ISSUES
+
+1. On the R4000 and R4400, branches, both the plain and the "likely" ones,
+ take 3 cycles to execute. (The fastest possible loop will take 4 cycles,
+ because of the delay insn.)
+
+ On the R4600, branches takes a single cycle
+
+ On the R8000, branches often take no noticable cycles, as they are
+ executed in a separate function unit..
+
+2. The R4000 and R4400 have a load latency of 4 cycles.
+
+3. On the R4000 and R4400, multiplies take a data-dependent number of
+ cycles, contrary to the SGI documentation. There seem to be 3 or 4
+ possible latencies.
+
+STATUS
+
+Good...