diff --git a/core/rexcode/riscv/instructions.odin b/core/rexcode/riscv/instructions.odin
index ccc5e8123..574d16256 100644
--- a/core/rexcode/riscv/instructions.odin
+++ b/core/rexcode/riscv/instructions.odin
@@ -15,14 +15,14 @@ Instruction_Flags :: bit_field u8 {
 }
 
 Instruction :: struct #packed {
-	ops:           [4]Operand `fmt:"v,operand_count"`, // 64 bytes
+	ops:           [4]Operand `fmt:"v,operand_count"`, // 40 bytes
 	mnemonic:      Mnemonic,                           // 2
 	operand_count: u8,                                 // 1
 	flags:         Instruction_Flags,                  // 1
 	length:        u8,                                 // 1 -- always 4 for non-C
 	_:             [3]u8,                              // 3
 }
-#assert(size_of(Instruction) == 72)
+#assert(size_of(Instruction) == 48)
 
 // =============================================================================
 // Builders (shape spelled out, comma-separated)
diff --git a/core/rexcode/riscv/operands.odin b/core/rexcode/riscv/operands.odin
index 2a244a5f1..946432464 100644
--- a/core/rexcode/riscv/operands.odin
+++ b/core/rexcode/riscv/operands.odin
@@ -44,9 +44,8 @@ Operand :: struct #packed {
 	},
 	kind: Operand_Kind,
 	size: u8,
-	_:   [6]u8,
 }
-#assert(size_of(Operand) == 16)
+#assert(size_of(Operand) == 10)
 
 @(require_results)
 op_reg    :: #force_inline proc "contextless" (r: Register)        -> Operand { return Operand{reg = r, kind = .REGISTER, size = 4} }