掌機 - Q8 - Assembly - SELECT、START、VOL

參考資料：
http://nano.lichee.pro/
https://mangopi.org/mangopi_r
https://www.allwinnertech.com/index.php?c=product&a=index&pid=4

暫存器


main.s

    .global _start
      
    .equiv CCU_BASE,              0x01c20000
    .equiv GPIO_BASE,             0x01c20800
    .equiv UART1_BASE,            0x01c25400
    .equiv TP_BASE,               0x01c24800
 
    .equiv PLL_PERIPH_CTRL_REG,   0x0028
    .equiv AHB_APB_HCLKC_CFG_REG, 0x0054
    .equiv BUS_CLK_GATING_REG2,   0x0068
    .equiv BUS_SOFT_RST_REG2,     0x02d0

    .equiv TP_CTRL_REG0,         0x00
    .equiv TP_CTRL_REG1,         0x04
    .equiv TP_CTRL_REG2,         0x08
    .equiv TP_CTRL_REG3,         0x0c
    .equiv TP_INT_FIFO_CTRL_REG, 0x10
    .equiv TP_INT_FIFO_STAT_REG, 0x14
    .equiv TP_COM_DATA_REG,      0x1c
    .equiv TP_DATA_REG,          0x24
    
    .equiv PA,        (0x24 * 0) 
    .equiv PORT_CFG0, 0x00
    .equiv PORT_DATA, 0x10
    .equiv UART_RBR,  0x0000
    .equiv UART_DLL,  0x0000
    .equiv UART_DLH,  0x0004
    .equiv UART_IER,  0x0004
    .equiv UART_IIR,  0x0008
    .equiv UART_LCR,  0x000c
    .equiv UART_MCR,  0x0010
    .equiv UART_USR,  0x007c
     
    .arm
    .text
_start:
    .long 0xea000016
    .byte 'e', 'G', 'O', 'N', '.', 'B', 'T', '0'
    .long 0, __spl_size
    .byte 'S', 'P', 'L', 2
    .long 0, 0
    .long 0, 0, 0, 0, 0, 0, 0, 0
    .long 0, 0, 0, 0, 0, 0, 0, 0
     
_vector:
    b reset
    b .
    b .
    b .
    b .
    b .
    b .
    b .
     
reset:
    ldr r4, =CCU_BASE
    ldr r1, =0x80041800
    str r1, [r4, #PLL_PERIPH_CTRL_REG]
    ldr r1, =0x00003180
    str r1, [r4, #AHB_APB_HCLKC_CFG_REG]
    
    ldr r4, =GPIO_BASE
    ldr r1, =0x5520
    str r1, [r4, #(PA + PORT_CFG0)]
    
    ldr r4, =CCU_BASE
    ldr r1, =(1 << 21)
    str r1, [r4, #BUS_CLK_GATING_REG2]
    str r1, [r4, #BUS_SOFT_RST_REG2]
    
    ldr r4, =UART1_BASE
    ldr r1, =0x00
    str r1, [r4, #UART_IER]
    ldr r1, =0xf7
    str r1, [r4, #UART_IIR]
    ldr r1, =0x00
    str r1, [r4, #UART_MCR]
    ldr r1, [r4, #UART_LCR]
    orr r1, #(1 << 7)
    str r1, [r4, #UART_LCR]
    ldr r1, =54
    str r1, [r4, #UART_DLL]
    ldr r1, =0x00
    str r1, [r4, #UART_DLH]
    ldr r1, [r4, #UART_LCR]
    bic r1, #(1 << 7)
    str r1, [r4, #UART_LCR]
    ldr r1, [r4, #UART_LCR]
    bic r1, #0x1f
    orr r1, #0x03
    str r1, [r4, #UART_LCR]

    ldr r4, =TP_BASE
    ldr r1, =(3 << 20) | (1 << 16) | (1 << 0)
    str r1, [r4, #TP_CTRL_REG0]
    ldr r1, =(1 << 5) | (1 << 4) | (1 << 1)
    str r1, [r4, #TP_CTRL_REG1]
0:
    ldr r0, [r4, #TP_DATA_REG]
    lsr r0, #4
    bl uart_print_byte

    ldr r1, =10000
1:
    subs r1, #1
    bne 1b
    b 0b

uart_print_byte:
    push {r4, lr}
    ldr r4, =UART1_BASE
0:
    ldr r1, [r4, #UART_USR]
    tst r1, #(1 << 1)
    beq 0b
    strb r0, [r4, #UART_RBR]
    pop {r4, pc}

uart_print_4byte:
    push {r4, lr}
    mov r4, r0
    lsr r0, #24
    bl uart_print_byte
 
    mov r0, r4
    lsr r0, #16
    bl uart_print_byte
     
    mov r0, r4
    lsr r0, #8
    bl uart_print_byte
     
    mov r0, r4
    bl uart_print_byte
    pop {r4, pc}

    .end