decode: Index minor op table with insn bits for opcode 30

This comprises the 64-bit rotate and mask instructions.  In order to
reduce the table index to 3 bits, we combine rldcl and rdlcr into a
single op (OP_RLDCX), and choose the right mask at execute time based
on bit 1 of the instruction word.

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

decode1.vhdl

@@ -26,6 +26,7 @@ architecture behaviour of decode1 is
         type major_rom_array_t is array(0 to 63) of decode_rom_t;
         type minor_valid_array_t is array(0 to 1023) of std_ulogic;
         type op_19_subop_array_t is array(0 to 7) of decode_rom_t;
+        type op_30_subop_array_t is array(0 to 7) of decode_rom_t;
         type minor_rom_array_2_t is array(0 to 3) of decode_rom_t;
 
 	type decode_rom_array_t is array(ppc_insn_t) of decode_rom_t;
@@ -112,17 +113,16 @@ architecture behaviour of decode1 is
 		others   => illegal_inst
         );
 
-	constant decode_op_30_array : decode_rom_array_t := (
+	constant decode_op_30_array : op_30_subop_array_t := (
 		--                unit     internal     in1         in2          in3   out   const const const CR   CR   cry  cry  ldst  BR   sgn  upd  rsrv mul  mul  rc    lk   sgl
 		--                               op                                          1     2     3     in   out  in   out  len        ext             32  sgn             pipe
-		PPC_ILLEGAL    =>       (ALU,    OP_ILLEGAL,   NONE,       NONE,        NONE, NONE, NONE, NONE, NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		2#010#   =>       (ALU,    OP_RLDIC,     RS,         NONE,        NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
-		PPC_RLDCL      =>       (ALU,    OP_RLDCL,     RS,         RB,          NONE, RA,   NONE, MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		2#000#   =>       (ALU,    OP_RLDICL,    RS,         NONE,        NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
-		PPC_RLDCR      =>       (ALU,    OP_RLDCR,     RS,         RB,          NONE, RA,   NONE, MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		2#001#   =>       (ALU,    OP_RLDICR,    RS,         NONE,        NONE, RA,   SH,   ME,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
-		PPC_RLDIC      =>       (ALU,    OP_RLDIC,     RS,         NONE,        NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		2#011#   =>       (ALU,    OP_RLDIMI,    RA,         RS,          NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
-		PPC_RLDICL     =>       (ALU,    OP_RLDICL,    RS,         NONE,        NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+                -- rldcl, rldcr
-		PPC_RLDICR     =>       (ALU,    OP_RLDICR,    RS,         NONE,        NONE, RA,   SH,   ME,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		2#100#   =>       (ALU,    OP_RLDCX,     RS,         RB,          NONE, RA,   NONE, MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
-		PPC_RLDIMI     =>       (ALU,    OP_RLDIMI,    RA,         RS,          NONE, RA,   SH,   MB,   NONE, '0', '0', '0', '0', NONE, '0', '0', '0', '0', '0', '0', RC,   '0', '1'),
+		others   => illegal_inst
-		others   => decode_rom_init
         );
 
 	-- Note: reformat with column -t -o ' '
@@ -280,6 +280,7 @@ begin
 		variable ppc_insn: ppc_insn_t;
                 variable majorop : major_opcode_t;
                 variable op_19_bits: std_ulogic_vector(2 downto 0);
+                variable op_30_bits: std_ulogic_vector(2 downto 0);
 	begin
 		v := r;
 
@@ -645,29 +646,7 @@ begin
                         end if;
 
                 elsif majorop = "011110" then
-                        if    std_match(f_in.insn, "---------------------------1000-") then
+                        v.decode := decode_op_30_array(to_integer(unsigned(f_in.insn(4 downto 2))));
-				report "PPC_rldcl";
-				ppc_insn := PPC_RLDCL;
-			elsif std_match(f_in.insn, "---------------------------1001-") then
-				report "PPC_rldcr";
-				ppc_insn := PPC_RLDCR;
-			elsif std_match(f_in.insn, "---------------------------010--") then
-				report "PPC_rldic";
-				ppc_insn := PPC_RLDIC;
-			elsif std_match(f_in.insn, "---------------------------000--") then
-				report "PPC_rldicl";
-				ppc_insn := PPC_RLDICL;
-			elsif std_match(f_in.insn, "---------------------------001--") then
-				report "PPC_rldicr";
-				ppc_insn := PPC_RLDICR;
-			elsif std_match(f_in.insn, "---------------------------011--") then
-				report "PPC_rldimi";
-				ppc_insn := PPC_RLDIMI;
-			else
-				report "PPC_illegal";
-				ppc_insn := PPC_ILLEGAL;
-			end if;
-			v.decode := decode_op_30_array(ppc_insn);
 
                 elsif majorop = "111010" then
                         v.decode := decode_op_58_array(to_integer(unsigned(f_in.insn(1 downto 0))));

decode_types.vhdl

@@ -51,7 +51,7 @@ package decode_types is
 		OP_MTCRF, OP_MTOCRF, OP_MTSPR, OP_MUL_L64,
 		OP_MUL_H64, OP_MUL_H32, OP_NAND, OP_NEG, OP_NOR, OP_OR,
 		OP_ORC, OP_POPCNTB, OP_POPCNTD, OP_POPCNTW, OP_PRTYD,
-		OP_PRTYW, OP_RLDCL, OP_RLDCR, OP_RLDIC, OP_RLDICL, OP_RLDICR,
+		OP_PRTYW, OP_RLDCX, OP_RLDIC, OP_RLDICL, OP_RLDICR,
 		OP_RLDIMI, OP_RLWIMI, OP_RLWINM, OP_RLWNM, OP_SETB, OP_SLD,
 		OP_SLW, OP_SRAD, OP_SRADI, OP_SRAW, OP_SRAWI, OP_SRD, OP_SRW,
 		OP_SUBF, OP_SUBFE, OP_SUBFME, OP_SYNC, OP_TD, OP_TDI, OP_TW,

execute1.vhdl

@@ -274,11 +274,12 @@ begin
 				when OP_PRTYW =>
 					result := ppc_prtyw(e_in.read_data1);
 					result_en := 1;
-				when OP_RLDCL =>
+				when OP_RLDCX =>
+                                        if e_in.insn(1) = '0' then
                                                 result := ppc_rldcl(e_in.read_data1, e_in.read_data2, e_in.const2(5 downto 0));
-					result_en := 1;
+                                        else
-				when OP_RLDCR =>
                                                 result := ppc_rldcr(e_in.read_data1, e_in.read_data2, e_in.const2(5 downto 0));
+                                        end if;
 					result_en := 1;
 				when OP_RLDICL =>
 					result := ppc_rldicl(e_in.read_data1, e_in.const1(5 downto 0), e_in.const2(5 downto 0));