From 3d6f41f7367e5ef31048667f35cd3e087b616ab1 Mon Sep 17 00:00:00 2001
From: SowinskiBraeden <braeden@sowinski.dev>
Date: Fri, 14 Nov 2025 18:12:51 -0800
Subject: [PATCH] simplify factorial

---
 factorial   | Bin 13536 -> 13536 bytes
 factorial.s |  22 ++++++++++------------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/factorial b/factorial
index 384a46d31fd1f917bf071b7156894ebda93519ba..a6aa3da9b933ce06852fa637814c1f4ea040301f 100755
GIT binary patch
delta 200
zcmaEm`5<$G1Y_<*$@iR786aTlW<kbaMv+fREf3|=`9iO+<&<OH!|?6=W4Xr76-*tx
zvL4O<8SBKuJ^r76@$vuv|4|<N>kqwV_c(rl5oo|<Re@mM-#}p~|3$;*R)N`alP557
zY*x@WU^J8!fZ7A4WWY2VgBY5)8dO|va-)GeWA5aW26?<G`FW`fNr}a&@yUtBn_UcT
Nm>8#SZZwW(1OUq<JD&gm

delta 204
zcmaEm`5<$G1Y_w$$@iRd86aTpW<kbaMiHB;uSw@-DHhy&dgS!$IjdeemELgOT*1`A
zs~YOj`P8HNKVzLhxX1tVFW&zD|3AuufBm7?>>kGtFaizn=zJ49SymvJmlec;h`p%T
zTq`hJZnJ{E0i&Um0Msrhr3j|k7!=XO)u7^PlN$}(8A~UhG|1ykN-R!|PX-bUDfxMu
QT?}oQ80T(oG>&Hk0P;pXxBvhE

diff --git a/factorial.s b/factorial.s
index 0979c06..8ec9ce4 100644
--- a/factorial.s
+++ b/factorial.s
@@ -2,31 +2,29 @@
 .global _start
 
 # factorial
-# - rdi as input number
-# - rax as result
+# - rdi (n) as input number
+# - rax (r) as result
 factorial:
-    push rbp
-    mov rbp, rsp
-
-    cmp rdi, 1
-    jle base_case      # if n <= 1 return 1
+    cmp rdi, 1         # compare n to 1
+    jle done           # if n <= 1 return (r = 1)
 
     push rdi           # save n
-    dec rdi            # rdi = n-1
-    call factorial     # rax = factorial(n-1)
+    dec rdi            # rdi = n - 1
+    call factorial     # rax = factorial(n - 1)
 
     pop rdx            # rdx = original n
-    imul rax, rdx      # rax = factorial(n-1) * n
+    imul rax, rdx      # rax = factorial(n - 1) * n
     jmp done
 
 base_case:
     mov rax, 1
 
 done:
-    mov rsp, rbp
-    pop rbp
     ret
 
+# prints number as decimal
+# from rax register
+# just to demo, don't explain
 print_rax_digit:
     sub rsp, 16