From d45f882710896eb52445107cf36616baef67efcc Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Thu, 21 Dec 2023 09:47:43 -0500
Subject: [PATCH] Factor out file-loading logic

---
 fasm/2015/1/problem.asm | 22 ++++------------------
 fasm/lib/file.inc       | 27 +++++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 18 deletions(-)
 create mode 100644 fasm/lib/file.inc

diff --git a/fasm/2015/1/problem.asm b/fasm/2015/1/problem.asm
index bc02954..ca25292 100644
--- a/fasm/2015/1/problem.asm
+++ b/fasm/2015/1/problem.asm
@@ -2,31 +2,20 @@ format ELF64 executable 3
 include "lib/linux_syscall.inc"
 include "lib/itoa.inc"
 include "lib/print.inc"
+include "lib/file.inc"
 
 segment readable executable
 entry main
 
 main:
-	;; Determine the file size of the input file
-	stat input_filename, file_stat
-
-	;; Open a file descriptor for the input file
-	open input_filename, 0
-	mov [input_fd], rax
-
-        ;; Map the input file into memory
-	mmap 0, [file_stat.st_size], PROT_READ, MAP_PRIVATE, [input_fd], 0
-	mov [input], rax
-
-	;; Close the input file
-	close [input_fd]
+	mov rdi, input_filename
+	call load_file
 
 	call part_1
 
 	call part_2
 
-	;; Unmap the mapped file
-	munmap [input], [file_stat.st_size]
+	call unload_file
 
 	;; Done!
 	exit 0
@@ -118,10 +107,7 @@ part_2:
 
 segment readable writable
 input_filename db '../data/2015/1/input.txt', 0
-input_fd dq -1
-input dq -1
 part_1_verbiage db 'Part 1: '
 part_1_answer db '      ', 0
 part_2_verbiage db 'Part 2: '
 part_2_answer db '      ', 0
-file_stat s_stat
diff --git a/fasm/lib/file.inc b/fasm/lib/file.inc
new file mode 100644
index 0000000..3c6978a
--- /dev/null
+++ b/fasm/lib/file.inc
@@ -0,0 +1,27 @@
+input_fd dq -1
+input dq -1
+file_stat s_stat
+
+;;; The input filename should be in rdi
+load_file:
+	mov r8, rdi
+	;; Determine the file size of the input file
+	stat r8, file_stat
+
+	;; Open a file descriptor for the input file
+	open r8, 0
+	mov [input_fd], rax
+
+        ;; Map the input file into memory
+	mmap 0, [file_stat.st_size], PROT_READ, MAP_PRIVATE, [input_fd], 0
+	mov [input], rax
+
+	;; Close the input file
+	close [input_fd]
+	ret
+
+unload_file:
+	;; Unmap the mapped file
+	munmap [input], [file_stat.st_size]
+
+	ret
\ No newline at end of file