simplify _loop so that the "prologe" is shorter and the jump is back into

the first < 5 bytes

test_cases/backwards.asm

@@ -6,16 +6,13 @@ use64
 
 public _loop
 _loop:
-	xor eax, eax
-	inc eax
-	mov rbx, rdx ; RDX is overwritten by mul
-@again:
-	cmp rbx, 0
-	je @loop_end
+	mov rax, rcx
+@loop_loop:
 	mul rcx
-	dec rbx
-	jmp @again
-@loop_end:
+	nop
+	nop
+	nop
+	loop @loop_loop ; lol
 	ret
 
 public _tail_recursion

test_cases/backwards.h

@@ -1,12 +1,11 @@
 #pragma once
 extern "C" {
 	/**
-	* Raises @num @cnt times
+	* $$ x*x * (x-1)! $$
 	*
-	* @param num
 	* @param cnt
 	*/
-	uint32_t _loop(uint32_t num, uint32_t cnt);
+	uint32_t _loop(uint32_t x);
 
 	/**
 	* Computes factorial

test_cases/main.cpp

@@ -32,10 +32,10 @@ TEST_CASE("Advanced instruction functions work as expected, unhokked") {
 }
 
 TEST_CASE("Loops & tail recursion work as expected, unhook") {
-	REQUIRE(_loop(2, 3) == 8);
-	REQUIRE(_loop(5, 3) == 125);
-	REQUIRE(_loop(5, 0) == 1);
-	REQUIRE(_loop(5, 1) == 5);
+	REQUIRE(_loop(1) == 1);
+	REQUIRE(_loop(2) == 4);
+	REQUIRE(_loop(3) == 18);
+	REQUIRE(_loop(5) == 25*24);
 
 	REQUIRE(_tail_recursion(0) == 1);
 	REQUIRE(_tail_recursion(1) == 1);