tillitis-key/hw/application_fpga/fw/tk1/start.S
Michael Cardell Widerkrantz d77654bb8e
fw: No .data or .bss segment
We don't use any .data or .bss segment at all to keep all the firmware
variables in the stack in protected fw_ram.

Signed-off-by: Daniel Lublin <daniel@lublin.se>
2023-03-14 10:25:02 +01:00

58 lines
797 B
ArmAsm

/*
* Copyright (C) 2022 - Tillitis AB
* SPDX-License-Identifier: GPL-2.0-only
*/
.section ".text.init"
.globl _start
_start:
li x1, 0
li x2, 0
li x3, 0
li x4, 0
li x5, 0
li x6, 0
li x7, 0
li x8, 0
li x9, 0
li x10,0
li x11,0
li x12,0
li x13,0
li x14,0
li x15,0
li x16,0
li x17,0
li x18,0
li x19,0
li x20,0
li x21,0
li x22,0
li x23,0
li x24,0
li x25,0
li x26,0
li x27,0
li x28,0
li x29,0
li x30,0
li x31,0
/* Clear all RAM */
li a0, 0x40000000 // TK1_RAM_BASE
li a1, 0x40020000 // TK1_RAM_BASE + TK1_RAM_SIZE
clear:
sw zero, 0(a0)
addi a0, a0, 4
blt a0, a1, clear
/*
* Init stack at top of fw_ram. Leave 16 byte for entering our first function
*/
li sp, 0xd00003f0 // 1 kiB - 16 byte in FW_RAM
call main
loop:
j loop