RISC-V: Add sext.[bh] and zext.[bhw] pseudo instructions.

https://github.com/riscv/riscv-asm-manual/pull/61

We aleady have sext.w, so just add sext.b, sext.h, zext.b, zext.h
and zext.w.  In a certain sense, zext.b is not a pseudo - It is an
alias of andi.  Similarly, sext.b and sext.h are aliases of other
rvb instructions, when we enable b extension; But they are pseudos
when we just enable rvi.  However, this patch does not consider the
rvb cases.  Besides, zext.w is only valid in rv64.

gas/
    * config/tc-riscv.c (riscv_ext): New function.  Use md_assemblef
    to expand the zext and sext pseudos, to give them a chance to be
    expanded into c-ext instructions.
    (macro): Handle M_ZEXTH, M_ZEXTW, M_SEXTB and M_SEXTH.
    * testsuite/gas/riscv/ext.s: New testcase.
    * testsuite/gas/riscv/ext-32.d: Likewise.
    * testsuite/gas/riscv/ext-64.d: Likewise.
include/
    * opcode/riscv.h (M_ZEXTH, M_ZEXTW, M_SEXTB, M_SEXTH.): Added.
opcodes/
    * riscv-opc.c (riscv_opcodes): Add sext.[bh] and zext.[bhw].

5 files changed, 171 insertions, 0 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index d657f87..6672da4 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,5 +1,15 @@
 2020-12-10  Nelson Chu  <nelson.chu@sifive.com>
 
+	* config/tc-riscv.c (riscv_ext): New function.  Use md_assemblef
+	to expand the zext and sext pseudos, to give them a chance to be
+	expanded into c-ext instructions.
+	(macro): Handle M_ZEXTH, M_ZEXTW, M_SEXTB and M_SEXTH.
+	* testsuite/gas/riscv/ext.s: New testcase.
+	* testsuite/gas/riscv/ext-32.d: Likewise.
+	* testsuite/gas/riscv/ext-64.d: Likewise.
+
+2020-12-10  Nelson Chu  <nelson.chu@sifive.com>
+
 	* config/tc-riscv.c (riscv_multi_subset_supports): Handle INSN_CLASS_ZICSR
 	and INSN_CLASS_ZIFENCEI.
 	* testsuite/gas/riscv/march-imply-i.s: New testcase.
diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index dfdbadf..ca7e52a 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -1433,6 +1433,23 @@ load_const (int reg, expressionS *ep)
     }
 }
 
+/* Zero extend and sign extend byte/half-word/word.  */
+
+static void
+riscv_ext (int destreg, int srcreg, unsigned shift, bfd_boolean sign)
+{
+  if (sign)
+    {
+      md_assemblef ("slli x%d, x%d, 0x%x", destreg, srcreg, shift);
+      md_assemblef ("srai x%d, x%d, 0x%x", destreg, destreg, shift);
+    }
+  else
+    {
+      md_assemblef ("slli x%d, x%d, 0x%x", destreg, srcreg, shift);
+      md_assemblef ("srli x%d, x%d, 0x%x", destreg, destreg, shift);
+    }
+}
+
 /* Expand RISC-V assembly macros into one or more instructions.  */
 static void
 macro (struct riscv_cl_insn *ip, expressionS *imm_expr,
@@ -1554,6 +1571,22 @@ macro (struct riscv_cl_insn *ip, expressionS *imm_expr,
       riscv_call (rd, rs1, imm_expr, *imm_reloc);
       break;
 
+    case M_ZEXTH:
+      riscv_ext (rd, rs1, xlen - 16, FALSE);
+      break;
+
+    case M_ZEXTW:
+      riscv_ext (rd, rs1, xlen - 32, FALSE);
+      break;
+
+    case M_SEXTB:
+      riscv_ext (rd, rs1, xlen - 8, TRUE);
+      break;
+
+    case M_SEXTH:
+      riscv_ext (rd, rs1, xlen - 16, TRUE);
+      break;
+
     default:
       as_bad (_("Macro %s not implemented"), ip->insn_mo->name);
       break;
diff --git a/gas/testsuite/gas/riscv/ext-32.d b/gas/testsuite/gas/riscv/ext-32.d
new file mode 100644
index 0000000..918c9c8
--- /dev/null
+++ b/gas/testsuite/gas/riscv/ext-32.d
@@ -0,0 +1,39 @@
+#as: -march=rv32i
+#source: ext.s
+#objdump: -d
+
+.*:[ 	]+file format .*
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+0:[ 	]+0ff57513[ 	]+zext.b[ 	]+a0,a0
+[ 	]+4:[ 	]+01051513[ 	]+slli[ 	]+a0,a0,0x10
+[ 	]+8:[ 	]+01055513[ 	]+srli[ 	]+a0,a0,0x10
+[ 	]+c:[ 	]+01851513[ 	]+slli[ 	]+a0,a0,0x18
+[ 	]+10:[ 	]+41855513[ 	]+srai[ 	]+a0,a0,0x18
+[ 	]+14:[ 	]+01051513[ 	]+slli[ 	]+a0,a0,0x10
+[ 	]+18:[ 	]+41055513[ 	]+srai[ 	]+a0,a0,0x10
+[ 	]+1c:[ 	]+0ff67593[ 	]+zext.b[ 	]+a1,a2
+[ 	]+20:[ 	]+01061593[ 	]+slli[ 	]+a1,a2,0x10
+[ 	]+24:[ 	]+0105d593[ 	]+srli[ 	]+a1,a1,0x10
+[ 	]+28:[ 	]+01861593[ 	]+slli[ 	]+a1,a2,0x18
+[ 	]+2c:[ 	]+4185d593[ 	]+srai[ 	]+a1,a1,0x18
+[ 	]+30:[ 	]+01061593[ 	]+slli[ 	]+a1,a2,0x10
+[ 	]+34:[ 	]+4105d593[ 	]+srai[ 	]+a1,a1,0x10
+[ 	]+38:[ 	]+0ff57513[ 	]+zext.b[ 	]+a0,a0
+[ 	]+3c:[ 	]+0542[ 	]+slli[ 	]+a0,a0,0x10
+[ 	]+3e:[ 	]+8141[ 	]+srli[ 	]+a0,a0,0x10
+[ 	]+40:[ 	]+0562[ 	]+slli[ 	]+a0,a0,0x18
+[ 	]+42:[ 	]+8561[ 	]+srai[ 	]+a0,a0,0x18
+[ 	]+44:[ 	]+0542[ 	]+slli[ 	]+a0,a0,0x10
+[ 	]+46:[ 	]+8541[ 	]+srai[ 	]+a0,a0,0x10
+[ 	]+48:[ 	]+0ff67593[ 	]+zext.b[ 	]+a1,a2
+[ 	]+4c:[ 	]+01061593[ 	]+slli[ 	]+a1,a2,0x10
+[ 	]+50:[ 	]+81c1[ 	]+srli[ 	]+a1,a1,0x10
+[ 	]+52:[ 	]+01861593[ 	]+slli[ 	]+a1,a2,0x18
+[ 	]+56:[ 	]+85e1[ 	]+srai[ 	]+a1,a1,0x18
+[ 	]+58:[ 	]+01061593[ 	]+slli[ 	]+a1,a2,0x10
+[ 	]+5c:[ 	]+85c1[ 	]+srai[ 	]+a1,a1,0x10
+#...
diff --git a/gas/testsuite/gas/riscv/ext-64.d b/gas/testsuite/gas/riscv/ext-64.d
new file mode 100644
index 0000000..49d109b
--- /dev/null
+++ b/gas/testsuite/gas/riscv/ext-64.d
@@ -0,0 +1,51 @@
+#as: -march=rv64i -defsym __64_bit__=1
+#source: ext.s
+#objdump: -d
+
+.*:[ 	]+file format .*
+
+
+Disassembly of section .text:
+
+0+000 <target>:
+[ 	]+0:[ 	]+0ff57513[ 	]+zext.b[ 	]+a0,a0
+[ 	]+4:[ 	]+03051513[ 	]+slli[ 	]+a0,a0,0x30
+[ 	]+8:[ 	]+03055513[ 	]+srli[ 	]+a0,a0,0x30
+[ 	]+c:[ 	]+03851513[ 	]+slli[ 	]+a0,a0,0x38
+[ 	]+10:[ 	]+43855513[ 	]+srai[ 	]+a0,a0,0x38
+[ 	]+14:[ 	]+03051513[ 	]+slli[ 	]+a0,a0,0x30
+[ 	]+18:[ 	]+43055513[ 	]+srai[ 	]+a0,a0,0x30
+[ 	]+1c:[ 	]+0ff67593[ 	]+zext.b[ 	]+a1,a2
+[ 	]+20:[ 	]+03061593[ 	]+slli[ 	]+a1,a2,0x30
+[ 	]+24:[ 	]+0305d593[ 	]+srli[ 	]+a1,a1,0x30
+[ 	]+28:[ 	]+03861593[ 	]+slli[ 	]+a1,a2,0x38
+[ 	]+2c:[ 	]+4385d593[ 	]+srai[ 	]+a1,a1,0x38
+[ 	]+30:[ 	]+03061593[ 	]+slli[ 	]+a1,a2,0x30
+[ 	]+34:[ 	]+4305d593[ 	]+srai[ 	]+a1,a1,0x30
+[ 	]+38:[ 	]+02051513[ 	]+slli[ 	]+a0,a0,0x20
+[ 	]+3c:[ 	]+02055513[ 	]+srli[ 	]+a0,a0,0x20
+[ 	]+40:[ 	]+0005051b[ 	]+sext.w[ 	]+a0,a0
+[ 	]+44:[ 	]+02061593[ 	]+slli[ 	]+a1,a2,0x20
+[ 	]+48:[ 	]+0205d593[ 	]+srli[ 	]+a1,a1,0x20
+[ 	]+4c:[ 	]+0006059b[ 	]+sext.w[ 	]+a1,a2
+[ 	]+50:[ 	]+0ff57513[ 	]+zext.b[ 	]+a0,a0
+[ 	]+54:[ 	]+1542[ 	]+slli[ 	]+a0,a0,0x30
+[ 	]+56:[ 	]+9141[ 	]+srli[ 	]+a0,a0,0x30
+[ 	]+58:[ 	]+1562[ 	]+slli[ 	]+a0,a0,0x38
+[ 	]+5a:[ 	]+9561[ 	]+srai[ 	]+a0,a0,0x38
+[ 	]+5c:[ 	]+1542[ 	]+slli[ 	]+a0,a0,0x30
+[ 	]+5e:[ 	]+9541[ 	]+srai[ 	]+a0,a0,0x30
+[ 	]+60:[ 	]+0ff67593[ 	]+zext.b[ 	]+a1,a2
+[ 	]+64:[ 	]+03061593[ 	]+slli[ 	]+a1,a2,0x30
+[ 	]+68:[ 	]+91c1[ 	]+srli[ 	]+a1,a1,0x30
+[ 	]+6a:[ 	]+03861593[ 	]+slli[ 	]+a1,a2,0x38
+[ 	]+6e:[ 	]+95e1[ 	]+srai[ 	]+a1,a1,0x38
+[ 	]+70:[ 	]+03061593[ 	]+slli[ 	]+a1,a2,0x30
+[ 	]+74:[ 	]+95c1[ 	]+srai[ 	]+a1,a1,0x30
+[ 	]+76:[ 	]+1502[ 	]+slli[ 	]+a0,a0,0x20
+[ 	]+78:[ 	]+9101[ 	]+srli[ 	]+a0,a0,0x20
+[ 	]+7a:[ 	]+2501[ 	]+sext.w[ 	]+a0,a0
+[ 	]+7c:[ 	]+02061593[ 	]+slli[ 	]+a1,a2,0x20
+[ 	]+80:[ 	]+9181[ 	]+srli[ 	]+a1,a1,0x20
+[ 	]+82:[ 	]+0006059b[ 	]+sext.w[ 	]+a1,a2
+#...
diff --git a/gas/testsuite/gas/riscv/ext.s b/gas/testsuite/gas/riscv/ext.s
new file mode 100644
index 0000000..f957134
--- /dev/null
+++ b/gas/testsuite/gas/riscv/ext.s
@@ -0,0 +1,38 @@
+target:
+	.option norvc
+	zext.b	a0, a0
+	zext.h	a0, a0
+	sext.b	a0, a0
+	sext.h	a0, a0
+
+	zext.b	a1, a2
+	zext.h	a1, a2
+	sext.b	a1, a2
+	sext.h	a1, a2
+
+.ifdef __64_bit__
+	zext.w	a0, a0
+	sext.w	a0, a0
+
+	zext.w	a1, a2
+	sext.w	a1, a2
+.endif
+
+	.option rvc
+	zext.b	a0, a0
+	zext.h	a0, a0
+	sext.b	a0, a0
+	sext.h	a0, a0
+
+	zext.b	a1, a2
+	zext.h	a1, a2
+	sext.b	a1, a2
+	sext.h	a1, a2
+
+.ifdef __64_bit__
+	zext.w	a0, a0
+	sext.w	a0, a0
+
+	zext.w	a1, a2
+	sext.w	a1, a2
+.endif