diff --git a/elf.inc b/elf.inc
index a155e5b..31e4e12 100644
--- a/elf.inc
+++ b/elf.inc
@@ -118,6 +118,11 @@ elf_binary_calculate_fields:
 
 	pop	rax
 	mov	qword [program_code_section_header.offset], rax
+	;
+	; above needs to be:
+	;
+	assert elf_binary_headers_length + 0x2a + 0x0e + 0x10 = 0xc0
+
 
 	mov	edi, eax
 	add	edi, elf_binary.base_address
diff --git a/elf_test.asm b/elf_test.asm
index 5102346..52506f9 100644
--- a/elf_test.asm
+++ b/elf_test.asm
@@ -33,9 +33,19 @@ entry $
 	mov	ecx, program_code.length
 	call	elf_binary_calculate_fields
 
+	mov	edi, 1
+	cmp	qword [elf_header.start_address], 0x400078
+	jne	exit
+
+	mov	edi, 2
+	cmp	qword [elf_header.section_header_offset], 0xc0
+	jne	exit
+
 	;
 	; exit cleanly
 	;
 	xor 	edi, edi
+
+exit:
 	mov 	eax, SYS_EXIT
 	syscall