[RFC PATCH v1] RISC-V: Support Zicond extension

Sat Jan 21 00:29:34 GMT 2023

*** Zicond is not FROZEN at this time. Do not merge until FROZEN. ***

This implements the Zicond (conditional integer operations) extension,
as of version 1.0-draft-20230120.

The Zicond extension acts as a building block for branchless sequences
including conditional-arithmetic, conditional-logic and
conditional-select/move.
The following instructions constitute Zicond:
  - czero.eqz rd, rs1, rs2  =>  rd = (rs2 == 0) ? 0 : rs1
  - czero.nez rd, rs1, rs2  =>  rd = (rs2 != 0) ? 0 : rs1

See
  https://github.com/riscv/riscv-zicond/releases/download/v1.0-draft-20230120/riscv-zicond_1.0-draft-20230120.pdf
for the proposed specification and usage details.

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_multi_subset_supports): Recognize
        INSN_CLASS_XVENTANACONDOPS.
	(riscv_multi_subset_supports_ext): Recognize
	INSN_CLASS_XVENTANACONDOPS,

gas/ChangeLog:

	* testsuite/gas/riscv/zicond.d: New test.
	* testsuite/gas/riscv/zicond.s: New test.

include/ChangeLog:

	* opcode/riscv-opc.h (MATCH_CZERO_EQZ): Define.
	(MASK_CZERO_EQZ): Define.
	(MATCH_CZERO_NEZ): Define,
	(MASK_CZERO_NEZ): Define.
	(DECLARE_INSN): Add czero.eqz and czero.nez.
	* opcode/riscv.h (enum riscv_insn_class): Add
        INSN_CLASS_ZICOND

opcodes/ChangeLog:

	* riscv-opc.c: Add czero.eqz and czero.nez.

Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
---

 bfd/elfxx-riscv.c                |  5 +++++
 gas/testsuite/gas/riscv/zicond.d | 12 ++++++++++++
 gas/testsuite/gas/riscv/zicond.s |  3 +++
 include/opcode/riscv-opc.h       |  8 ++++++++
 include/opcode/riscv.h           |  1 +
 opcodes/riscv-opc.c              |  4 ++++
 6 files changed, 33 insertions(+)
 create mode 100644 gas/testsuite/gas/riscv/zicond.d
 create mode 100644 gas/testsuite/gas/riscv/zicond.s

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index a48d6300a1f..ec69c7fdc4d 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1168,6 +1168,7 @@ static struct riscv_supported_ext riscv_supported_std_z_ext[] =
   {"zicbom",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zicbop",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
   {"zicboz",		ISA_SPEC_CLASS_DRAFT,		1, 0,  0 },
+  {"zicond",		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 },
@@ -2267,6 +2268,8 @@ riscv_multi_subset_supports (riscv_parse_subset_t *rps,
       return riscv_subset_supports (rps, "zicbop");
     case INSN_CLASS_ZICBOZ:
       return riscv_subset_supports (rps, "zicboz");
+    case INSN_CLASS_ZICOND:
+      return riscv_subset_supports (rps, "zicond");
     case INSN_CLASS_ZICSR:
       return riscv_subset_supports (rps, "zicsr");
     case INSN_CLASS_ZIFENCEI:
@@ -2435,6 +2438,8 @@ riscv_multi_subset_supports_ext (riscv_parse_subset_t *rps,
       return "zicbop";
     case INSN_CLASS_ZICBOZ:
       return "zicboz";
+    case INSN_CLASS_ZICOND:
+      return "zicond";
     case INSN_CLASS_ZICSR:
       return "zicsr";
     case INSN_CLASS_ZIFENCEI:
diff --git a/gas/testsuite/gas/riscv/zicond.d b/gas/testsuite/gas/riscv/zicond.d
new file mode 100644
index 00000000000..7a79ee6a716
--- /dev/null
+++ b/gas/testsuite/gas/riscv/zicond.d
@@ -0,0 +1,12 @@
+#as: -march=rv64i_zicond
+#source: zicond.s
+#objdump: -d
+
+.*:[	 ]+file format .*
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[	 ]+0:[	 ]+0ec5d533[	 ]+czero.eqz[	 ]+a0,a1,a2
+[	 ]+4:[	 ]+0ee6f533[	 ]+czero.nez[	 ]+a0,a3,a4
diff --git a/gas/testsuite/gas/riscv/zicond.s b/gas/testsuite/gas/riscv/zicond.s
new file mode 100644
index 00000000000..4e5edd5056a
--- /dev/null
+++ b/gas/testsuite/gas/riscv/zicond.s
@@ -0,0 +1,3 @@
+target:
+	czero.eqz	a0, a1, a2
+	czero.nez	a0, a3, a4
diff --git a/include/opcode/riscv-opc.h b/include/opcode/riscv-opc.h
index 32b160660d3..c99756e47e1 100644
--- a/include/opcode/riscv-opc.h
+++ b/include/opcode/riscv-opc.h
@@ -2187,6 +2187,11 @@
 #define MASK_CBO_INVAL 0xfff07fff
 #define MATCH_CBO_ZERO 0x40200f
 #define MASK_CBO_ZERO 0xfff07fff
+/* Zicond instructions. */
+#define MATCH_CZERO_EQZ 0xe005033
+#define MASK_CZERO_EQZ 0xfe00707f
+#define MATCH_CZERO_NEZ 0xe007033
+#define MASK_CZERO_NEZ 0xfe00707f
 /* Zawrs intructions.  */
 #define MATCH_WRS_NTO 0x00d00073
 #define MASK_WRS_NTO 0xffffffff
@@ -3194,6 +3199,9 @@ DECLARE_INSN(cbo_clean, MATCH_CBO_CLEAN, MASK_CBO_CLEAN);
 DECLARE_INSN(cbo_flush, MATCH_CBO_FLUSH, MASK_CBO_FLUSH);
 DECLARE_INSN(cbo_inval, MATCH_CBO_INVAL, MASK_CBO_INVAL);
 DECLARE_INSN(cbo_zero, MATCH_CBO_ZERO, MASK_CBO_ZERO);
+/* Zicond instructions. */
+DECLARE_INSN(czero_eqz, MATCH_CZERO_EQZ, MASK_CZERO_EQZ)
+DECLARE_INSN(czero_nez, MATCH_CZERO_NEZ, MASK_CZERO_NEZ)
 /* Zawrs instructions.  */
 DECLARE_INSN(wrs_nto, MATCH_WRS_NTO, MASK_WRS_NTO)
 DECLARE_INSN(wrs_sto, MATCH_WRS_STO, MASK_WRS_STO)
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index 57bea48704d..dfab0502d49 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -379,6 +379,7 @@ enum riscv_insn_class
   INSN_CLASS_Q,
   INSN_CLASS_F_AND_C,
   INSN_CLASS_D_AND_C,
+  INSN_CLASS_ZICOND,
   INSN_CLASS_ZICSR,
   INSN_CLASS_ZIFENCEI,
   INSN_CLASS_ZIHINTPAUSE,
diff --git a/opcodes/riscv-opc.c b/opcodes/riscv-opc.c
index 639683e76b1..33cd4ab57d1 100644
--- a/opcodes/riscv-opc.c
+++ b/opcodes/riscv-opc.c
@@ -935,6 +935,10 @@ const struct riscv_opcode riscv_opcodes[] =
 {"cbo.inval",  0, INSN_CLASS_ZICBOM, "0(s)", MATCH_CBO_INVAL, MASK_CBO_INVAL, match_opcode, 0 },
 {"cbo.zero",   0, INSN_CLASS_ZICBOZ, "0(s)", MATCH_CBO_ZERO, MASK_CBO_ZERO, match_opcode, 0 },
 
+/* Zicond instructions.  */
+{"czero.eqz",  0, INSN_CLASS_ZICOND, "d,s,t", MATCH_CZERO_EQZ, MASK_CZERO_EQZ, match_opcode, 0 },
+{"czero.nez",  0, INSN_CLASS_ZICOND, "d,s,t", MATCH_CZERO_NEZ, MASK_CZERO_NEZ, match_opcode, 0 },
+
 /* Zawrs instructions.  */
 {"wrs.nto",    0, INSN_CLASS_ZAWRS, "", MATCH_WRS_NTO, MASK_WRS_NTO, match_opcode, 0 },
 {"wrs.sto",    0, INSN_CLASS_ZAWRS, "", MATCH_WRS_STO, MASK_WRS_STO, match_opcode, 0 },
-- 
2.34.1

