/* * minute - a port of the "mini" IOS replacement for the Wii U. * * Copyright (C) 2021 Roberto Van Eeden * * This code is licensed to you under the terms of the GNU GPL, version 2; * see file COPYING or http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt */ #ifdef LOLSERIAL_DEBUG #include "latte.h" .arm .globl lolserial_print .globl lolserial_lprint .section .text /* * the number of timer ticks to wait * each bit; might need manual adjustment * for particoular serial adapters, usually * the stable value is in the +5/-5 range */ .equ LOLSERIAL_WAIT_TICKS, 200 .equ GP_SENSORBAR, 0x00000100 @ arg:r0 string address lolserial_print: mov r1, #-1 @ arg:r0 string address @ arg:r1 max length lolserial_lprint: push {r4-r5} add r1, r0 @ end address in r1 ldr r5, =LT_REG_BASE @ latte registers base in r5 @ clear32(LT_GPIO_OWNER, GP_SENSORBAR) ldr r2, [r5, #0x0FC] bic r2, r2, #GP_SENSORBAR str r2, [r5, #0x0FC] @ set32(LT_GPIO_ENABLE, GP_SENSORBAR) ldr r2, [r5, #0x0DC] orr r2, r2, #GP_SENSORBAR str r2, [r5, #0x0DC] @ set32(LT_GPIO_DIR, GP_SENSORBAR) ldr r2, [r5, #0x0E4] orr r2, r2, #GP_SENSORBAR str r2, [r5, #0x0E4] @ set32(LT_GPIO_OUT, GP_SENSORBAR) ldr r2, [r5, #0x0E0] orr r2, r2, #GP_SENSORBAR str r2, [r5, #0x0E0] lolserial_send_string_loop: cmp r0, r1 @ ensure end address was not reached ldrneb r3, [r0], #1 @ load cur char in r3, increment r0 string ptr cmpne r3, #0 @ check for string null termination beq lolserial_send_string_end @ r3: bits to send (serial end bit, data byte, serial start bit) @ r3 = (1 << 9) | (r3:chr << 1) | (0 << 0) lsl r3, #1 orr r3, #0x200 @ loop over bits to send lolserial_send_char_loop: @ mask32(LT_GPIO_OUT, GP_SENSORBAR, bit ? GP_SENSORBAR : 0) tst r3, #1 ldr r2, [r5, #0x0E0] biceq r2, #GP_SENSORBAR orrne r2, #GP_SENSORBAR str r2, [r5, #0x0E0] @ wait for LOLSERIAL_WAIT_TICKS timer ticks ldr r2, [r5, #0x010] @ r2: current ticks adds r4, r2, #LOLSERIAL_WAIT_TICKS @ r4: wait time end timer_wait_overflow_loop: cmp r4, r2 ldr r2, [r5, #0x010] blo timer_wait_overflow_loop timer_wait_loop: cmp r4, r2 ldr r2, [r5, #0x010] bhi timer_wait_loop lsrs r3, #1 @ go to next bit bne lolserial_send_char_loop @ unless r3 is 0 (end bit sent) b lolserial_send_string_loop lolserial_send_string_end: pop {r4-r5} bx lr #endif /* LOLSERIAL_DEBUG */