1 files changed, 19 insertions, 0 deletions
diff --git a/riscv/insns/shlr.h b/riscv/insns/shlr.h
new file mode 100644
index 00000000..29801fa9
--- /dev/null
+++ b/riscv/insns/shlr.h
@@ -0,0 +1,19 @@
+require_extension('P');
+require_rv64;
+sreg_t sshamt = P_FIELD(RS2, 0, 8);
+if (sshamt < 0) {
+  __uint128_t shx;
+  if (sshamt < -64)
+    shx = 0;
+  else if (sshamt == -64)
+    shx = (RS1 >> 63) & 1;
+  else
+    shx = ((__uint128_t)RS1 << 1) >> (-sshamt);
+  WRITE_RD((uint64_t)((shx + 1) >> 1));
+} else {
+  if (sshamt >= 64)
+    WRITE_RD(0);
+  else
+    WRITE_RD(RS1 << sshamt);
+}
+