add spr to fast reg converter

diff --git a/src/soc/regfile/util.py b/src/soc/regfile/util.py
index 1587e550d0a445406bee600cb2215af16044b5b9..c7d691cefda9873b1eb084f4ec458566d90e0bce 100644 (file)
--- a/src/soc/regfile/util.py
+++ b/src/soc/regfile/util.py
@@ -12,3 +12,18 @@ def fast_reg_to_spr(spr_num):
         return SPR.SRR0.value
     elif spr_num == FastRegs.SRR1:
         return SPR.SRR1.value
+
+
+def spr_to_fast_reg(spr_num):
+    if not isinstance(spr_num, str):
+        spr_num = spr_dict[spr_num].SPR
+    if spr_num == 'CTR':
+        return FastRegs.CTR
+    elif spr_num == 'LR':
+        return FastRegs.LR
+    elif spr_num == 'TAR':
+        return FastRegs.TAR
+    elif spr_num == 'SRR0':
+        return FastRegs.SRR0
+    elif spr_num == 'SRR1':
+        return FastRegs.SRR1