From: Paul Mackerras <paulus@ozlabs.org>
Date: Thu, 27 Jul 2023 04:58:09 +0000 (+1000)
Subject: Implement set[n]bc[r] instructions
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fd8c0000c03c00be91aee83f578ccf18ccbcb5bb;p=microwatt.git

Implement set[n]bc[r] instructions

This implements the setbc, setnbc, setbcr and setnbcr instructions.
Because the insn_type_t type already has 64 elements, this uses the
existing OP_SETB for the new instructions, and has execute1 compute
different results depending on bits 6-9 of the instruction.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---

diff --git a/execute1.vhdl b/execute1.vhdl
index e6cfd3e..e537048 100644
--- a/execute1.vhdl
+++ b/execute1.vhdl
@@ -836,14 +836,27 @@ begin
 		end if;
                 misc_result <= mfcr_result;
             when "110" =>
-                -- setb
-                bfa := insn_bfa(e_in.insn);
-                crbit := to_integer(unsigned(bfa)) * 4;
+                -- setb and set[n]bc[r]
                 setb_result := (others => '0');
-                if cr_in(31 - crbit) = '1' then
-                    setb_result := (others => '1');
-                elsif cr_in(30 - crbit) = '1' then
-                    setb_result(0) := '1';
+                if e_in.insn(9) = '0' then
+                    -- setb
+                    bfa := insn_bfa(e_in.insn);
+                    crbit := to_integer(unsigned(bfa)) * 4;
+                    if cr_in(31 - crbit) = '1' then
+                        setb_result := (others => '1');
+                    elsif cr_in(30 - crbit) = '1' then
+                        setb_result(0) := '1';
+                    end if;
+                else
+                    -- set[n]bc[r]
+                    crbit := to_integer(unsigned(insn_bi(e_in.insn)));
+                    if (cr_in(31 - crbit) xor e_in.insn(6)) = '1' then
+                        if e_in.insn(7) = '0' then
+                            setb_result(0) := '1';
+                        else
+                            setb_result := (others => '1');
+                        end if;
+                    end if;
                 end if;
                 misc_result <= setb_result;
             when others =>
diff --git a/predecode.vhdl b/predecode.vhdl
index 41b26ad..58b17e3 100644
--- a/predecode.vhdl
+++ b/predecode.vhdl
@@ -336,6 +336,10 @@ architecture behaviour of predecoder is
         2#0_00101_11010#  =>  INSN_prtyd,
         2#0_00100_11010#  =>  INSN_prtyw,
         2#0_00100_00000#  =>  INSN_setb,
+        2#0_01100_00000#  =>  INSN_setb, -- setbc
+        2#0_01101_00000#  =>  INSN_setb, -- setbcr
+        2#0_01110_00000#  =>  INSN_setb, -- setnbc
+        2#0_01111_00000#  =>  INSN_setb, -- setnbcr
         2#0_01111_10010#  =>  INSN_slbia,
         2#0_00000_11011#  =>  INSN_sld,
         2#0_00000_11000#  =>  INSN_slw,