Hexagon (target/hexagon) Clean up handling of modifier registers

Currently, the register number (MuN) for modifier registers is the
modifier register number rather than the index into hex_gpr.  This
patch changes MuN to the hex_gpr index, which is consistent with
the handling of control registers.

Note that HELPER(fcircadd) needs the CS register corresponding to the
modifier register specified in the instruction.  We create a TCGv
variable "CS" to hold the value to pass to the helper.

Reviewed-by: Brian Cain <bcain@quicinc.com>
Signed-off-by: Taylor Simpson <ltaylorsimpson@gmail.com>
Message-Id: <20231210220712.491494-2-ltaylorsimpson@gmail.com>
Signed-off-by: Brian Cain <bcain@quicinc.com>

4 files changed, 17 insertions, 16 deletions

diff --git a/target/hexagon/gen_tcg.h b/target/hexagon/gen_tcg.h
index d992059..1c4391b 100644
--- a/target/hexagon/gen_tcg.h
+++ b/target/hexagon/gen_tcg.h
@@ -68,15 +68,14 @@
     do { \
         TCGv tcgv_siV = tcg_constant_tl(siV); \
         tcg_gen_mov_tl(EA, RxV); \
-        gen_helper_fcircadd(RxV, RxV, tcgv_siV, MuV, \
-                            hex_gpr[HEX_REG_CS0 + MuN]); \
+        gen_helper_fcircadd(RxV, RxV, tcgv_siV, MuV, CS); \
     } while (0)
 #define GET_EA_pcr(SHIFT) \
     do { \
         TCGv ireg = tcg_temp_new(); \
         tcg_gen_mov_tl(EA, RxV); \
         gen_read_ireg(ireg, MuV, (SHIFT)); \
-        gen_helper_fcircadd(RxV, RxV, ireg, MuV, hex_gpr[HEX_REG_CS0 + MuN]); \
+        gen_helper_fcircadd(RxV, RxV, ireg, MuV, CS); \
     } while (0)
 
 /* Instructions with multiple definitions */
@@ -113,7 +112,7 @@
         TCGv ireg = tcg_temp_new(); \
         tcg_gen_mov_tl(EA, RxV); \
         gen_read_ireg(ireg, MuV, SHIFT); \
-        gen_helper_fcircadd(RxV, RxV, ireg, MuV, hex_gpr[HEX_REG_CS0 + MuN]); \
+        gen_helper_fcircadd(RxV, RxV, ireg, MuV, CS); \
         LOAD; \
     } while (0)
 
@@ -427,7 +426,7 @@
         TCGv BYTE G_GNUC_UNUSED = tcg_temp_new(); \
         tcg_gen_mov_tl(EA, RxV); \
         gen_read_ireg(ireg, MuV, SHIFT); \
-        gen_helper_fcircadd(RxV, RxV, ireg, MuV, hex_gpr[HEX_REG_CS0 + MuN]); \
+        gen_helper_fcircadd(RxV, RxV, ireg, MuV, CS); \
         STORE; \
     } while (0)
 
diff --git a/target/hexagon/gen_tcg_funcs.py b/target/hexagon/gen_tcg_funcs.py
index f5246ce..02d93bc 100755
--- a/target/hexagon/gen_tcg_funcs.py
+++ b/target/hexagon/gen_tcg_funcs.py
@@ -99,10 +99,15 @@ def genptr_decl(f, tag, regtype, regid, regno):
             hex_common.bad_register(regtype, regid)
     elif regtype == "M":
         if regid == "u":
-            f.write(f"    const int {regtype}{regid}N = " f"insn->regno[{regno}];\n")
             f.write(
-                f"    TCGv {regtype}{regid}V = hex_gpr[{regtype}{regid}N + "
-                "HEX_REG_M0];\n"
+                f"    const int {regN} = insn->regno[{regno}] + HEX_REG_M0;\n"
+            )
+            f.write(
+                f"    TCGv {regtype}{regid}V = hex_gpr[{regN}];\n"
+            )
+            f.write(
+                f"    TCGv CS G_GNUC_UNUSED = "
+                f"hex_gpr[{regN} - HEX_REG_M0 + HEX_REG_CS0];\n"
             )
         else:
             hex_common.bad_register(regtype, regid)
@@ -528,7 +533,7 @@ def gen_tcg_func(f, tag, regs, imms):
             ):
                 declared.append(f"{regtype}{regid}V")
                 if regtype == "M":
-                    declared.append(f"{regtype}{regid}N")
+                    declared.append("CS")
             elif hex_common.is_new_val(regtype, regid, tag):
                 declared.append(f"{regtype}{regid}N")
             else:
diff --git a/target/hexagon/idef-parser/parser-helpers.c b/target/hexagon/idef-parser/parser-helpers.c
index 4af0209..95f2b43 100644
--- a/target/hexagon/idef-parser/parser-helpers.c
+++ b/target/hexagon/idef-parser/parser-helpers.c
@@ -1541,10 +1541,8 @@ void gen_circ_op(Context *c,
                  HexValue *increment,
                  HexValue *modifier)
 {
-    HexValue cs = gen_tmp(c, locp, 32, UNSIGNED);
     HexValue increment_m = *increment;
     increment_m = rvalue_materialize(c, locp, &increment_m);
-    OUT(c, locp, "gen_read_reg(", &cs, ", HEX_REG_CS0 + MuN);\n");
     OUT(c,
         locp,
         "gen_helper_fcircadd(",
@@ -1555,7 +1553,7 @@ void gen_circ_op(Context *c,
         &increment_m,
         ", ",
         modifier);
-    OUT(c, locp, ", ", &cs, ");\n");
+    OUT(c, locp, ", CS);\n");
 }
 
 HexValue gen_locnt_op(Context *c, YYLTYPE *locp, HexValue *src)
@@ -2080,9 +2078,9 @@ void emit_arg(Context *c, YYLTYPE *locp, HexValue *arg)
             char reg_id[5];
             reg_compose(c, locp, &(arg->reg), reg_id);
             EMIT_SIG(c, ", %s %s", type, reg_id);
-            /* MuV register requires also MuN to provide its index */
+            /* MuV register requires also CS for circular addressing*/
             if (arg->reg.type == MODIFIER) {
-                EMIT_SIG(c, ", int MuN");
+                EMIT_SIG(c, ", TCGv CS");
             }
         }
         break;
diff --git a/target/hexagon/macros.h b/target/hexagon/macros.h
index f99390e..1376d6c 100644
--- a/target/hexagon/macros.h
+++ b/target/hexagon/macros.h
@@ -462,8 +462,7 @@ static inline TCGv gen_read_ireg(TCGv result, TCGv val, int shift)
 #define fPM_CIRI(REG, IMM, MVAL) \
     do { \
         TCGv tcgv_siV = tcg_constant_tl(siV); \
-        gen_helper_fcircadd(REG, REG, tcgv_siV, MuV, \
-                            hex_gpr[HEX_REG_CS0 + MuN]); \
+        gen_helper_fcircadd(REG, REG, tcgv_siV, MuV, CS); \
     } while (0)
 #else
 #define fEA_IMM(IMM)        do { EA = (IMM); } while (0)