RISC-V: Prefetch hint instructions and operand set

This commit adds 'Zicbop' hint instructions.

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_multi_subset_supports): Add handling for
	new instruction class.

gas/ChangeLog:

	* config/tc-riscv.c (riscv_ip): Add handling for new operand
	type 'f' (32-byte aligned pseudo S-type immediate for prefetch
	hints).
	(validate_riscv_insn): Likewise.

include/ChangeLog:

	* opcode/riscv-opc.h (MATCH_PREFETCH_I, MASK_PREFETCH_I,
	MATCH_PREFETCH_R, MASK_PREFETCH_R, MATCH_PREFETCH_W,
	MASK_PREFETCH_W): New macros.
	* opcode/riscv.h (enum riscv_insn_class): Add new instruction
	class INSN_CLASS_ZICBOP.

opcodes/ChangeLog:

	* riscv-dis.c (print_insn_args): Add handling for new operand
	type.
	* riscv-opc.c (riscv_opcodes): Add prefetch hint instructions.

bfd/elfxx-riscv.c

@@ -1172,6 +1172,7 @@ static struct riscv_supported_ext riscv_supported_std_ext[] =
 
 static struct riscv_supported_ext riscv_supported_std_z_ext[] =
 {
+  {"zicbop",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zicsr",		ISA_SPEC_CLASS_20191213,	2, 0,  0 },
   {"zicsr",		ISA_SPEC_CLASS_20190608,	2, 0,  0 },
   {"zifencei",		ISA_SPEC_CLASS_20191213,	2, 0,  0 },
@@ -2316,6 +2317,8 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
     {
     case INSN_CLASS_I:
       return riscv_subset_supports (rps, "i");
+    case INSN_CLASS_ZICBOP:
+      return riscv_subset_supports (rps, "zicbop");
     case INSN_CLASS_ZICSR:
       return riscv_subset_supports (rps, "zicsr");
     case INSN_CLASS_ZIFENCEI:

gas/config/tc-riscv.c

@@ -1179,6 +1179,7 @@ validate_riscv_insn (const struct riscv_opcode *opc, int length)
 	case 'j': used_bits |= ENCODE_ITYPE_IMM (-1U); break;
 	case 'a': used_bits |= ENCODE_JTYPE_IMM (-1U); break;
 	case 'p': used_bits |= ENCODE_BTYPE_IMM (-1U); break;
+	case 'f': /* Fall through.  */
 	case 'q': used_bits |= ENCODE_STYPE_IMM (-1U); break;
 	case 'u': used_bits |= ENCODE_UTYPE_IMM (-1U); break;
 	case 'z': break; /* Zero immediate.  */
@@ -3191,6 +3192,23 @@ riscv_ip (char *str, struct riscv_cl_insn *ip, expressionS *imm_expr,
 	      imm_expr->X_op = O_absent;
 	      continue;
 
+	    case 'f': /* Prefetch offset, pseudo S-type but lower 5-bits zero.  */
+	      if (riscv_handle_implicit_zero_offset (imm_expr, asarg))
+		continue;
+	      my_getExpression (imm_expr, asarg);
+	      check_absolute_expr (ip, imm_expr, false);
+	      if (((unsigned) (imm_expr->X_add_number) & 0x1fU)
+		  || imm_expr->X_add_number >= (signed) RISCV_IMM_REACH / 2
+		  || imm_expr->X_add_number < -(signed) RISCV_IMM_REACH / 2)
+		as_bad (_("improper prefetch offset (%ld)"),
+			(long) imm_expr->X_add_number);
+	      ip->insn_opcode |=
+		ENCODE_STYPE_IMM ((unsigned) (imm_expr->X_add_number) &
+				  ~ 0x1fU);
+	      imm_expr->X_op = O_absent;
+	      asarg = expr_end;
+	      continue;
+
 	    default:
 	    unknown_riscv_ip_operand:
 	      as_fatal (_("internal: unknown argument type `%s'"),

gas/testsuite/gas/riscv/zicbop-fail.d

@@ -0,0 +1,3 @@
+#as: -march=rv64g_zicbop
+#source: zicbop-fail.s
+#error_output: zicbop-fail.l

gas/testsuite/gas/riscv/zicbop-fail.l

@@ -0,0 +1,4 @@
+.*: Assembler messages:
+.*: Error: improper prefetch offset \(2048\)
+.*: Error: improper prefetch offset \(-2080\)
+.*: Error: improper prefetch offset \(255\)

gas/testsuite/gas/riscv/zicbop-fail.s

@@ -0,0 +1,4 @@
+target:
+	prefetch.i	2048(x1)
+	prefetch.r	-0x820(x16)
+	prefetch.w	+0xff(x31)

gas/testsuite/gas/riscv/zicbop.d

@@ -0,0 +1,12 @@
+#as: -march=rv64g_zicbop
+#source: zicbop.s
+#objdump: -dr
+
+.*:[ 	]+file format .*
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+[0-9a-f]+:[ 	]+0200e013[ 	]+prefetch\.i[ 	]+32\(ra\)
+[ 	]+[0-9a-f]+:[ 	]+80186013[ 	]+prefetch\.r[ 	]+-2048\(a6\)
+[ 	]+[0-9a-f]+:[ 	]+7e3fe013[ 	]+prefetch\.w[ 	]+2016\(t6\)

gas/testsuite/gas/riscv/zicbop.s

@@ -0,0 +1,4 @@
+target:
+	prefetch.i	0x20(x1)
+	prefetch.r	-2048(x16)
+	prefetch.w	+0x7e0(x31)

include/opcode/riscv-opc.h

@@ -2029,6 +2029,13 @@
 #define MASK_HSV_W 0xfe007fff
 #define MATCH_HSV_D 0x6e004073
 #define MASK_HSV_D 0xfe007fff
+/* Zicbop hint instructions. */
+#define MATCH_PREFETCH_I 0x6013
+#define MASK_PREFETCH_I 0x1f07fff
+#define MATCH_PREFETCH_R 0x106013
+#define MASK_PREFETCH_R 0x1f07fff
+#define MATCH_PREFETCH_W 0x306013
+#define MASK_PREFETCH_W 0x1f07fff
 /* Unprivileged Counter/Timers CSR addresses.  */
 #define CSR_CYCLE 0xc00
 #define CSR_TIME 0xc01

include/opcode/riscv.h

@@ -388,6 +388,7 @@ enum riscv_insn_class
   INSN_CLASS_V,
   INSN_CLASS_ZVEF,
   INSN_CLASS_SVINVAL,
+  INSN_CLASS_ZICBOP,
 };
 
 /* This structure holds information for a particular instruction.  */

opcodes/riscv-dis.c

@@ -424,6 +424,10 @@ print_insn_args (const char *oparg, insn_t l, bfd_vma pc, disassemble_info *info
 	  print (info->stream, "%d", (int)EXTRACT_STYPE_IMM (l));
 	  break;
 
+	case 'f':
+	  print (info->stream, "%d", (int)EXTRACT_STYPE_IMM (l));
+	  break;
+
 	case 'a':
 	  info->target = EXTRACT_JTYPE_IMM (l) + pc;
 	  (*info->print_address_func) (info->target, info);

opcodes/riscv-opc.c

@@ -388,6 +388,9 @@ const struct riscv_opcode riscv_opcodes[] =
 {"lw",          0, INSN_CLASS_I, "d,o(s)",    MATCH_LW, MASK_LW, match_opcode, INSN_DREF|INSN_4_BYTE },
 {"lw",          0, INSN_CLASS_I, "d,A",       0, (int) M_LW, match_never, INSN_MACRO },
 {"not",         0, INSN_CLASS_I, "d,s",       MATCH_XORI|MASK_IMM, MASK_XORI|MASK_IMM, match_opcode, INSN_ALIAS },
+{"prefetch.i",  0, INSN_CLASS_ZICBOP, "f(s)", MATCH_PREFETCH_I, MASK_PREFETCH_I, match_opcode, 0 },
+{"prefetch.r",  0, INSN_CLASS_ZICBOP, "f(s)", MATCH_PREFETCH_R, MASK_PREFETCH_R, match_opcode, 0 },
+{"prefetch.w",  0, INSN_CLASS_ZICBOP, "f(s)", MATCH_PREFETCH_W, MASK_PREFETCH_W, match_opcode, 0 },
 {"ori",         0, INSN_CLASS_I, "d,s,j",     MATCH_ORI, MASK_ORI, match_opcode, 0 },
 {"or",          0, INSN_CLASS_C, "Cs,Cw,Ct",  MATCH_C_OR, MASK_C_OR, match_opcode, INSN_ALIAS },
 {"or",          0, INSN_CLASS_C, "Cs,Ct,Cw",  MATCH_C_OR, MASK_C_OR, match_opcode, INSN_ALIAS },