From 905ed60d44d1ffe9b4955d43255938b36121a031 Mon Sep 17 00:00:00 2001
From: timschuerewegen <4085193+timschuerewegen@users.noreply.github.com>
Date: Fri, 16 Apr 2021 22:46:08 -0600
Subject: [PATCH] Import Tim's version

---
 payload/payload.S | 60 +++++++++++++++++++++++++++++++++++------------
 1 file changed, 45 insertions(+), 15 deletions(-)

diff --git a/payload/payload.S b/payload/payload.S
index 7385aa3..59f69a0 100644
--- a/payload/payload.S
+++ b/payload/payload.S
@@ -1,3 +1,5 @@
+.syntax unified
+
 .section .text
 .global _start
 
@@ -44,23 +46,51 @@ foo:
 	nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;
 	nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;nop;
 
+// __disable_interrupt();
+CPSID    I
 
+// LTDC_Layer1->CR = 0; // disable layer
+// LTDC_Layer1->DCCR = 0xFF0000FF; // blue
+LDR      R0, =0x50001084
+MOVS     R1, #0
+STR      R1, [R0, #0x00]
+LDR      R1, =0xFF0000FF
+STR      R1, [R0, #0x18]
 
-mov r2, #0
-mov r4, #4
-loop:
-    ldr r0, src
-    ldr r1, dst
+// LTDC_Layer2->CR = 0; // disable layer
+LDR      R0, =0x50001104
+MOVS     R1, #0
+STR      R1, [R0, #0x00]
 
-    add r0, r0, r2
-    add r1, r1, r2
+// LTDC->SRCR = 1; // reload shadow registers now
+// LTDC->BCCR = 0x000000; // black
+LDR      R0, =0x50001000
+MOVS     R1, #1
+STR      R1, [R0, #0x24]
+MOVS     R1, #0
+STR      R1, [R0, #0x2C]
 
-    ldr r3, [r0]
-    str r3, [r1]
+// uint32_t *src = (uint32_t*)0x08000000;
+// uint32_t *dst = (uint32_t*)0x24000000;
+// for (int len = 0; len < 0x20000 / 4; len++)
+// {
+// 	*dst++ = *src++;
+// }
+MOV      R0, #0x08000000
+MOV      R1, #0x24000000
+MOV      R2, #0x8000
+loop1:
+LDR      R3, [R0], #4
+STR      R3, [R1], #4
+SUBS     R2, R2, #1
+BNE      loop1
 
-	add r2, r2, r4
-
-    b loop
-
-src: .long 0x08000000
-dst: .long 0x24000000
+// while (1)
+// {
+//   WWDG1->CR = 0x69;
+// }
+LDR      R0, =0x50003000
+MOVS     R1, #0x69
+loop2:
+STR      R1, [R0, #0x00]
+B        loop2