diff --git a/gas/config/tc-aarch64.c b/gas/config/tc-aarch64.c
index e1762df395e..ba0a46227a7 100644
--- a/gas/config/tc-aarch64.c
+++ b/gas/config/tc-aarch64.c
@@ -3394,6 +3394,11 @@ parse_shift (char **str, aarch64_opnd_info *operand, enum parse_shift_mode mode)
 	}
       operand->shifter.amount = 0;
     }
+  else if (exp.X_op == O_big)
+    {
+      set_fatal_syntax_error (_("shift amount out of range"));
+      return FALSE;
+    }
   else if (exp.X_op != O_constant)
     {
       set_syntax_error (_("constant shift amount required"));
@@ -6438,10 +6443,19 @@ parse_operands (char *str, const aarch64_opcode *opcode)
 	  po_misc_or_fail (parse_shifter_operand_imm (&str, info,
 						      SHIFTED_ARITH_IMM));
 
+	  if (inst.reloc.exp.X_op != O_constant)
+	    {
+	      set_fatal_syntax_error (_(inst.reloc.exp.X_op == O_big
+					? "immediate out of range"
+					: "expected constant expression"));
+	      goto failure;
+	    }
+
 	  /* Try to coerce into shifted form if the immediate is out of
 	     range.  */
-	  if (inst.reloc.exp.X_add_number > 63 && (info->imm.value & 16) == 0
-	      && (inst.reloc.exp.X_add_number >> 4) <= 64
+	  if (inst.reloc.exp.X_add_number > 63
+	      && (inst.reloc.exp.X_add_number & 0xf) == 0
+	      && (inst.reloc.exp.X_add_number >> 4) <= 63
 	      && info->shifter.amount == 0)
 	    {
 	      info->shifter.amount = 4;
diff --git a/gas/testsuite/gas/aarch64/scbnds-immed.d b/gas/testsuite/gas/aarch64/scbnds-immed.d
new file mode 100644
index 00000000000..d11aac40b16
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/scbnds-immed.d
@@ -0,0 +1,16 @@
+#name: test valid scbnds immediates
+#as: -march=morello
+#objdump: -dr
+
+.*:     file format .*
+
+
+Disassembly of section \.text:
+
+.* <\.text>:
+.*:	c2c03820 	scbnds	c0, c1, #0x0
+.*:	c2d03820 	scbnds	c0, c1, #0x20
+.*:	c2dfb820 	scbnds	c0, c1, #0x3f
+.*:	c2c27820 	scbnds	c0, c1, #0x4, lsl #4
+.*:	c2c2f820 	scbnds	c0, c1, #0x5, lsl #4
+.*:	c2dff820 	scbnds	c0, c1, #0x3f, lsl #4
diff --git a/gas/testsuite/gas/aarch64/scbnds-immed.s b/gas/testsuite/gas/aarch64/scbnds-immed.s
new file mode 100644
index 00000000000..f45ea66ff78
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/scbnds-immed.s
@@ -0,0 +1,6 @@
+scbnds c0, c1, #0
+scbnds c0, c1, #32
+scbnds c0, c1, #63
+scbnds c0, c1, #64
+scbnds c0, c1, #80
+scbnds c0, c1, #1008
diff --git a/gas/testsuite/gas/aarch64/scbnds-invalid.d b/gas/testsuite/gas/aarch64/scbnds-invalid.d
new file mode 100644
index 00000000000..bdd0ce3f55e
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/scbnds-invalid.d
@@ -0,0 +1,4 @@
+#name: invalid scbnds instructions
+#as: -march=morello
+#source: scbnds-invalid.s
+#error_output: scbnds-invalid.l
diff --git a/gas/testsuite/gas/aarch64/scbnds-invalid.l b/gas/testsuite/gas/aarch64/scbnds-invalid.l
new file mode 100644
index 00000000000..a204c0aeee5
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/scbnds-invalid.l
@@ -0,0 +1,30 @@
+.*: Assembler messages:
+.*: Error: operand 2 must be a Capability register or a capability stack pointer register -- `scbnds c0,czr,#1'
+.*: Error: operand 1 must be a Capability register or a capability stack pointer register -- `scbnds czr,c0,#1'
+.*: Error: operand 1 must be a Capability register or a capability stack pointer register -- `scbnds czr,czr,#1'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#-1'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#65'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#66'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#67'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#68'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#69'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#70'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#71'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#72'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#73'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#74'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#75'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#76'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#77'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#78'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#79'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#81'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#1009'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#1024'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#1000000000000000000000001'
+.*: Error: shift amount out of range 0 to 63 at operand 3 -- `scbnds c0,c1,#1,lsl#-1'
+.*: Error: shift amount must be 4 at operand 3 -- `scbnds c0,c1,#1,lsl#2'
+.*: Error: shift amount must be 4 at operand 3 -- `scbnds c0,c1,#1,lsl#3'
+.*: Error: shift amount must be 4 at operand 3 -- `scbnds c0,c1,#1,lsl#5'
+.*: Error: shift amount out of range at operand 3 -- `scbnds c0,c1,#1,lsl#10000000000000000000000001'
+.*: Error: immediate out of range at operand 3 -- `scbnds c0,c1,#64,lsl#4'
diff --git a/gas/testsuite/gas/aarch64/scbnds-invalid.s b/gas/testsuite/gas/aarch64/scbnds-invalid.s
new file mode 100644
index 00000000000..4c1fab89edb
--- /dev/null
+++ b/gas/testsuite/gas/aarch64/scbnds-invalid.s
@@ -0,0 +1,29 @@
+scbnds c0, czr, #1
+scbnds czr, c0, #1
+scbnds czr, czr, #1
+scbnds c0, c1, #-1
+scbnds c0, c1, #65
+scbnds c0, c1, #66
+scbnds c0, c1, #67
+scbnds c0, c1, #68
+scbnds c0, c1, #69
+scbnds c0, c1, #70
+scbnds c0, c1, #71
+scbnds c0, c1, #72
+scbnds c0, c1, #73
+scbnds c0, c1, #74
+scbnds c0, c1, #75
+scbnds c0, c1, #76
+scbnds c0, c1, #77
+scbnds c0, c1, #78
+scbnds c0, c1, #79
+scbnds c0, c1, #81
+scbnds c0, c1, #1009
+scbnds c0, c1, #1024
+scbnds c0, c1, #1000000000000000000000001
+scbnds c0, c1, #1, lsl #-1
+scbnds c0, c1, #1, lsl #2
+scbnds c0, c1, #1, lsl #3
+scbnds c0, c1, #1, lsl #5
+scbnds c0, c1, #1, lsl #10000000000000000000000001
+scbnds c0, c1, #64, lsl #4
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index a13ff33ce43..c4c5841746a 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -2239,13 +2239,13 @@ operand_general_constraint_met_p (aarch64_feature_set features,
 				   _("shift amount must be 4"));
 		  return 0;
 		}
-	      if (!value_fit_unsigned_field_p (opnd->imm.value, 6))
-		{
-		  set_other_error (mismatch_detail, idx,
-				   _("immediate out of range"));
-		  return 0;
-		}
 	    }
+	    if (!value_fit_unsigned_field_p (opnd->imm.value, 6))
+	      {
+		set_other_error (mismatch_detail, idx,
+				 _("immediate out of range"));
+		return 0;
+	      }
 	  break;
 
 	case AARCH64_OPND_AIMM: