From a1010618a24474e4c8253d2fc1df300474bac609 Mon Sep 17 00:00:00 2001
From: Curtis McEnroe <programble@gmail.com>
Date: Fri, 2 Dec 2016 04:58:57 -0500
Subject: Add 32-bit hex formatting

---
 Makefile  |  2 +-
 day01.asm |  8 +++++++-
 lib.asm   | 19 +++++++++++++++++++
 3 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 lib.asm

diff --git a/Makefile b/Makefile
index df4adfd..7f63807 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ all: $(BINS)
 %: %.o
 	ld -o $@ $<
 
-%.o: %.asm sys.asm
+%.o: %.asm sys.asm lib.asm
 	nasm -f elf64 -o $@ $<
 
 clean:
diff --git a/day01.asm b/day01.asm
index 8ad4c66..fd31fce 100644
--- a/day01.asm
+++ b/day01.asm
@@ -1,4 +1,5 @@
 %include "sys.asm"
+%include "lib.asm"
 
 %define rPosX r8
 %define rPosY r9
@@ -65,5 +66,10 @@ _start:
   xor rPosY, rax
   sub rPosY, rax
 
-  lea rax, [rPosX + rPosY]
+  lea rdi, [rPosX + rPosY]
+  call hex32
+  push rax
+  syscall SYS_WRITE, FD_STDOUT, rsp, 8
+
+  xor rax, rax
 syscall SYS_EXIT, rax
diff --git a/lib.asm b/lib.asm
new file mode 100644
index 0000000..10d0e1c
--- /dev/null
+++ b/lib.asm
@@ -0,0 +1,19 @@
+section .rodata
+hexDigits: db '0123456789ABCDEF'
+
+section .text
+hex32:
+  push rbx
+  mov rbx, hexDigits
+  xor rax, rax
+
+%rep 8
+  shl rax, 8
+  mov al, dil
+  and al, 0x0F
+  xlatb
+  shr rdi, 4
+%endrep
+
+  pop rbx
+ret
-- 
cgit 1.4.1