🪃🪃

library/boundscheck.c

@@ -0,0 +1,23 @@
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int BoundsError(int d){
+    printf("You are trying to access memory that isn't yours.\n");
+    exit(1);
+}
+
+void BoundsCheck(int argc, void * start, ...){
+    va_list argptr;
+    va_start(argptr, start);
+    int index = 0;
+    while (argc){
+        argc--;
+        index = va_arg(argptr, int);
+        if(index > *(int*)start){
+            BoundsError(index);
+        }
+        start += sizeof(int);
+    }
+    va_end(argptr);
+}

library/boundscheck.s

@@ -0,0 +1,112 @@
+	.file	"boundscheck.c"
+	.text
+	.section	.rodata
+	.align 8
+.LC0:
+	.string	"You are trying to access memory that isn't yours."
+	.text
+	.globl	BoundsError
+	.type	BoundsError, @function
+BoundsError:
+.LFB6:
+	.cfi_startproc
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	subq	$16, %rsp
+	movl	%edi, -4(%rbp)
+	leaq	.LC0(%rip), %rax
+	movq	%rax, %rdi
+	call	puts@PLT
+	movl	$1, %edi
+	call	exit@PLT
+	.cfi_endproc
+.LFE6:
+	.size	BoundsError, .-BoundsError
+	.globl	BoundsCheck
+	.type	BoundsCheck, @function
+BoundsCheck:
+.LFB7:
+	.cfi_startproc
+	pushq	%rbp
+	.cfi_def_cfa_offset 16
+	.cfi_offset 6, -16
+	movq	%rsp, %rbp
+	.cfi_def_cfa_register 6
+	subq	$240, %rsp
+	movl	%edi, -228(%rbp)
+	movq	%rsi, -240(%rbp)
+	movq	%rdx, -160(%rbp)
+	movq	%rcx, -152(%rbp)
+	movq	%r8, -144(%rbp)
+	movq	%r9, -136(%rbp)
+	testb	%al, %al
+	je	.L3
+	movaps	%xmm0, -128(%rbp)
+	movaps	%xmm1, -112(%rbp)
+	movaps	%xmm2, -96(%rbp)
+	movaps	%xmm3, -80(%rbp)
+	movaps	%xmm4, -64(%rbp)
+	movaps	%xmm5, -48(%rbp)
+	movaps	%xmm6, -32(%rbp)
+	movaps	%xmm7, -16(%rbp)
+.L3:
+	movq	%fs:40, %rax
+	movq	%rax, -184(%rbp)
+	xorl	%eax, %eax
+	movl	$16, -208(%rbp)
+	movl	$48, -204(%rbp)
+	leaq	16(%rbp), %rax
+	movq	%rax, -200(%rbp)
+	leaq	-176(%rbp), %rax
+	movq	%rax, -192(%rbp)
+	movl	$0, -212(%rbp)
+	jmp	.L4
+.L8:
+	subl	$1, -228(%rbp)
+	movl	-208(%rbp), %eax
+	cmpl	$47, %eax
+	ja	.L5
+	movq	-192(%rbp), %rax
+	movl	-208(%rbp), %edx
+	movl	%edx, %edx
+	addq	%rdx, %rax
+	movl	-208(%rbp), %edx
+	addl	$8, %edx
+	movl	%edx, -208(%rbp)
+	jmp	.L6
+.L5:
+	movq	-200(%rbp), %rax
+	leaq	8(%rax), %rdx
+	movq	%rdx, -200(%rbp)
+.L6:
+	movl	(%rax), %eax
+	movl	%eax, -212(%rbp)
+	movq	-240(%rbp), %rax
+	movl	(%rax), %eax
+	cmpl	%eax, -212(%rbp)
+	jle	.L7
+	movl	-212(%rbp), %eax
+	movl	%eax, %edi
+	call	BoundsError
+.L7:
+	addq	$4, -240(%rbp)
+.L4:
+	cmpl	$0, -228(%rbp)
+	jne	.L8
+	nop
+	movq	-184(%rbp), %rax
+	subq	%fs:40, %rax
+	je	.L9
+	call	__stack_chk_fail@PLT
+.L9:
+	leave
+	.cfi_def_cfa 7, 8
+	ret
+	.cfi_endproc
+.LFE7:
+	.size	BoundsCheck, .-BoundsCheck
+	.ident	"GCC: (GNU) 14.2.1 20250207"
+	.section	.note.GNU-stack,"",@progbits