From: Tobias Platen <tplaten@posteo.de>
Date: Tue, 26 Jan 2021 19:27:40 +0000 (+0100)
Subject: [Bug 580] redirect MMU SPRs to the MMU
X-Git-Tag: convert-csv-opcode-to-binary~312
X-Git-Url: https://git.libre-soc.org/?p=soc.git;a=commitdiff_plain;h=eb30c83009e3a01162ea1de537884e0b8bf6a154

[Bug 580] redirect MMU SPRs to the MMU
---

diff --git a/src/soc/decoder/power_decoder2.py b/src/soc/decoder/power_decoder2.py
index 32cd7332..1633d191 100644
--- a/src/soc/decoder/power_decoder2.py
+++ b/src/soc/decoder/power_decoder2.py
@@ -725,7 +725,25 @@ class PowerDecodeSubset(Elaboratable):
         # set up instruction, pick fn unit
         # no op: defaults to OP_ILLEGAL
         comb += self.do_copy("insn_type", self.op_get("internal_op"))
-        comb += self.do_copy("fn_unit", self.op_get("function_unit"))
+
+        #function unit for decoded instruction
+        fn = self.op_get("function_unit")
+        spr = Signal(10, reset_less=True)
+        comb += spr.eq(decode_spr_num(self.dec.SPR)) # from XFX
+
+        # for first test only forward SPR 18 to mmu
+        with m.If(self.dec.op.internal_op == MicrOp.OP_MTSPR):
+            with m.If((spr == 18) | (spr == 19)):
+                comb += self.do_copy("fn_unit",Function.MMU)
+            with m.Else():
+                comb += self.do_copy("fn_unit",fn)
+        with m.If(self.dec.op.internal_op == MicrOp.OP_MFSPR):
+            with m.If((spr == 18) | (spr == 19)):
+                comb += self.do_copy("fn_unit",Function.MMU)
+            with m.Else():
+                comb += self.do_copy("fn_unit",fn)
+        with m.Else():
+            comb += self.do_copy("fn_unit",fn)
 
         # immediates
         if self.needs_field("zero_a", "in1_sel"):