From c09f3d0a7dc5b91c9cd1dd6261de3e91b7f5e38c Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Mon, 25 Dec 2023 04:58:22 -0500
Subject: [PATCH] Work on problem 2 in fasm

---
 fasm/2015/2/problem.asm | 66 +++++++++++++++++++++++++++++++++++++-
 fasm/bin/run            |  2 +-
 fasm/lib/string.inc     | 71 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 137 insertions(+), 2 deletions(-)
 create mode 100644 fasm/lib/string.inc

diff --git a/fasm/2015/2/problem.asm b/fasm/2015/2/problem.asm
index 2a461b0..63d72de 100644
--- a/fasm/2015/2/problem.asm
+++ b/fasm/2015/2/problem.asm
@@ -3,6 +3,7 @@ include "lib/linux_syscall.inc"
 include "lib/print.inc"
 include "lib/itoa.inc"
 include "lib/file.inc"
+include "lib/string.inc"
 
 segment readable executable
 entry main
@@ -11,8 +12,14 @@ main:
 	mov rdi, input_filename
 	call load_file
 
-	call part_1
+	mov r8, [input]
+	mov [input_pointer], r8
 
+.go:
+	call print_line
+	jmp .go
+
+	call unload_file
 	exit 0
 
 part_1:
@@ -24,10 +31,67 @@ part_1:
 	call print_c_string
 	ret
 
+print_line:
+	mov r11, 0
+	mov rdi, [input_pointer]
+	mov rsi, current_line
+	mov dl, 'x'
+	call copy_until_token_to_string
+
+	mov rdi, current_line
+	call atoi
+	add r11, rax
+
+	mov rdi, current_line
+	call string_length
+	add [input_pointer], rax
+	inc [input_pointer]
+
+	alarm r11
+
+	mov rdi, [input_pointer]
+	mov rsi, current_line
+	mov dl, 'x'
+	call copy_until_token_to_string
+
+	mov rdi, current_line
+	call atoi
+	add r11, rax
+
+	mov rdi, current_line
+	call string_length
+	add [input_pointer], rax
+	inc [input_pointer]
+
+	alarm r11
+
+	mov rdi, [input_pointer]
+	mov rsi, current_line
+	mov dl, 10
+	call copy_until_token_to_string
+
+	mov rdi, current_line
+	call atoi
+	add r11, rax
+
+	mov rdi, current_line
+	call string_length
+	add [input_pointer], rax
+	inc [input_pointer]
+
+	alarm r11
+
+	alarm 0
+	
+	ret
+
+
 segment readable writable
 input_filename db '../data/2015/2/input.txt', 0
+input_pointer dq -1
 part_1_verbiage db 'Part 1: '
 part_1_answer db '      ', 0
 part_2_verbiage db 'Part 2: '
 part_2_answer db '      ', 0
 number db '42069', 0
+current_line db '          ', 0
diff --git a/fasm/bin/run b/fasm/bin/run
index 584fb3f..5dfe308 100755
--- a/fasm/bin/run
+++ b/fasm/bin/run
@@ -3,4 +3,4 @@
 year=$1
 day=$2
 
-bin/fasm $year/$day/problem.asm $year/$day/problem && time ./$year/$day/problem
+bin/fasm $year/$day/problem.asm $year/$day/problem && strace ./$year/$day/problem
diff --git a/fasm/lib/string.inc b/fasm/lib/string.inc
new file mode 100644
index 0000000..4950e42
--- /dev/null
+++ b/fasm/lib/string.inc
@@ -0,0 +1,71 @@
+;;; rdi should contain the source to copy from
+;;; rsi should contain the destination pointer
+;;; rdx should contain the number of bytes to copy
+copy_mem_to_string:
+	cmp rdx, 0
+	jz .finish
+	mov r8, [rdi]
+	mov [rsi], r8
+	inc rsi
+	inc rdi
+	dec rdx
+	jmp copy_mem_to_string
+
+.finish:
+	mov byte [rsi], 0
+	ret
+
+;;; rdi should contain the source to copy from
+;;; rsi should contain the destination pointer
+copy_line_to_string:
+	mov rax, 0
+.start:
+	cmp byte [rdi], 10
+	jz .finish
+
+	mov r8, [rdi]
+	mov [rsi], r8
+
+	inc rsi
+	inc rdi
+	inc rax
+	jmp copy_line_to_string
+
+.finish:
+	mov byte [rsi], 0
+	ret
+
+;;; rdi should contain the source to copy from
+;;; rsi should contain the destination pointer
+;;; dl should contain the delimiter
+copy_until_token_to_string:
+	mov rax, 0
+.start:
+	cmp byte [rdi], dl
+	jz .finish
+
+	mov r8, [rdi]
+	mov [rsi], r8
+
+	inc rsi
+	inc rdi
+	inc rax
+	jmp copy_until_token_to_string
+
+.finish:
+	mov byte [rsi], 0
+	ret
+
+;;; rdi should contain the string to measure
+string_length:
+	mov rax, 0
+.start:
+	cmp byte [rdi], 0
+	jz .finish
+
+	inc rdi
+	inc rax
+	jmp string_length
+
+.finish:
+	ret