diff --git a/lib/std/zig/AstGen.zig b/lib/std/zig/AstGen.zig
index ccc870e363..74fbd03adb 100644
--- a/lib/std/zig/AstGen.zig
+++ b/lib/std/zig/AstGen.zig
@@ -8854,10 +8854,10 @@ fn asmExpr(
             return astgen.failNode(node, "assembly expression with no output must be marked volatile", .{});
         }
     }
-    if (full.outputs.len > 32) {
-        return astgen.failNode(full.outputs[32], "too many asm outputs", .{});
+    if (full.outputs.len >= 16) {
+        return astgen.failNode(full.outputs[16], "too many asm outputs", .{});
     }
-    var outputs_buffer: [32]Zir.Inst.Asm.Output = undefined;
+    var outputs_buffer: [15]Zir.Inst.Asm.Output = undefined;
     const outputs = outputs_buffer[0..full.outputs.len];
 
     var output_type_bits: u32 = 0;
@@ -8893,10 +8893,10 @@ fn asmExpr(
         }
     }
 
-    if (full.inputs.len > 32) {
+    if (full.inputs.len >= 32) {
         return astgen.failNode(full.inputs[32], "too many asm inputs", .{});
     }
-    var inputs_buffer: [32]Zir.Inst.Asm.Input = undefined;
+    var inputs_buffer: [31]Zir.Inst.Asm.Input = undefined;
     const inputs = inputs_buffer[0..full.inputs.len];
 
     for (full.inputs, 0..) |input_node, i| {
@@ -8912,7 +8912,7 @@ fn asmExpr(
         };
     }
 
-    var clobbers_buffer: [32]u32 = undefined;
+    var clobbers_buffer: [63]u32 = undefined;
     var clobber_i: usize = 0;
     if (full.first_clobber) |first_clobber| clobbers: {
         // asm ("foo" ::: "a", "b")
@@ -12932,14 +12932,14 @@ const GenZir = struct {
         }
         gz.astgen.extra.appendSliceAssumeCapacity(args.clobbers);
 
-        //  * 0b00000000_000XXXXX - `outputs_len`.
-        //  * 0b000000XX_XXX00000 - `inputs_len`.
-        //  * 0b0XXXXX00_00000000 - `clobbers_len`.
+        //  * 0b00000000_0000XXXX - `outputs_len`.
+        //  * 0b0000000X_XXXX0000 - `inputs_len`.
+        //  * 0b0XXXXXX0_00000000 - `clobbers_len`.
         //  * 0bX0000000_00000000 - is volatile
-        const small: u16 = @as(u16, @intCast(args.outputs.len)) |
-            @as(u16, @intCast(args.inputs.len << 5)) |
-            @as(u16, @intCast(args.clobbers.len << 10)) |
-            (@as(u16, @intFromBool(args.is_volatile)) << 15);
+        const small: u16 = @as(u16, @as(u4, @intCast(args.outputs.len))) << 0 |
+            @as(u16, @as(u5, @intCast(args.inputs.len))) << 4 |
+            @as(u16, @as(u6, @intCast(args.clobbers.len))) << 9 |
+            @as(u16, @intFromBool(args.is_volatile)) << 15;
 
         const new_index: Zir.Inst.Index = @enumFromInt(astgen.instructions.len);
         astgen.instructions.appendAssumeCapacity(.{
diff --git a/src/Sema.zig b/src/Sema.zig
index ad800c29a6..5dbf26f375 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -16661,9 +16661,9 @@ fn zirAsm(
     const extra = sema.code.extraData(Zir.Inst.Asm, extended.operand);
     const src = block.nodeOffset(extra.data.src_node);
     const ret_ty_src = block.src(.{ .node_offset_asm_ret_ty = extra.data.src_node });
-    const outputs_len: u5 = @truncate(extended.small);
-    const inputs_len: u5 = @truncate(extended.small >> 5);
-    const clobbers_len: u5 = @truncate(extended.small >> 10);
+    const outputs_len: u4 = @truncate(extended.small);
+    const inputs_len: u5 = @truncate(extended.small >> 4);
+    const clobbers_len: u6 = @truncate(extended.small >> 9);
     const is_volatile = @as(u1, @truncate(extended.small >> 15)) != 0;
     const is_global_assembly = sema.func_index == .none;
     const zir_tags = sema.code.instructions.items(.tag);