chore(snippets): move snippetss to src/

1 files changed, 21 insertions, 0 deletions

diff --git a/src/lib/allocate.s b/src/lib/allocate.s
new file mode 100644
index 0000000..fdd9bf8
--- /dev/null
+++ b/src/lib/allocate.s
@@ -0,0 +1,21 @@
+# void *allocate(int n)
+#
+# 	A naive memory allocator that simply retrieves some new space from the OS.
+# 	It is not possible to deallocate the memory again.
+.globl allocate
+.type allocate, @function
+allocate:
+	push %rdi
+	# 1. Find the current end of the data segment.
+	movq $12, %rax # brk
+	xorq %rdi, %rdi # 0 means we retrieve the current end.
+	syscall
+	# 2. Add the amount of memory we want to allocate.
+	pop %rdi # the argument
+	push %rax # current end, which is where the allocated memory will start
+	addq %rax, %rdi # compute the new end
+	movq $12, %rax # brk
+	syscall
+	pop %rax # the old end, which is the address of our allocated memory
+	ret
+