File content as of revision 0:98789a3f7363:

USART_ISR_Offset EQU 0x1C
USART_TDR_Offset EQU 0x28
USART2 EQU 0x40004400

   
    AREA asm_func, CODE, READONLY
; Export my_asm function location so that C compiler can find it and link
    EXPORT check_2_bit
check_2_bit

    PUSH {LR}
    ;R0 = GPIOx
    ;R1 = offset
    ;r2 = pin_number
    

    LDR R3, [R0, R1]
    
    LDR R0, =30
    SUBS R0,R2
    SUBS R0,R2    
    LSLS R3,R3,R0
    LSRS R3,#30
    
    ;MOVS R1,R3
    ;BL PRINT_HEXA
    MOVS R0,R3
    
    POP {PC}

;********************************************
;* Function:    UART_PUTCHAR
;* Brief:       
;* Input:       R0
;* Output:      
;********************************************
UART_PUTCHAR PROC
    PUSH {R0,R1,R2,R3,LR}
    LDR R2,=USART2
UT_WAIT_FOR_UART    
    LDR R1,[R2,#USART_ISR_Offset]; load status register
    MOVS R3, #(1 :SHL: 7) ;check TXE (bit 7)
    TST R1,R3
    BEQ UT_WAIT_FOR_UART ;loop here until ready
    STRH R0,[R2,#USART_TDR_Offset] ;transmit buffer is ready, fill it with new value 
    POP {R0,R1,R2,R3,PC}
    ENDP    
;********************************************

;********************************************
;* Function:    PRINT_DECIMAL
;* Brief:       
;* Input:       R1
;* Output:      
;********************************************
PRINT_DECIMAL PROC
    PUSH {R0,R2,LR}
    
    CMP R1, #0
    BNE CONTINUE
    
    
    LDR R0, =48
    BL UART_PUTCHAR
    B EXIT
 
CONTINUE
    
    LDR R2,=1000000; delitel

DIVIDE    
    CMP R1,R2
    BHS ONE_SIGN
    BL DIVIDE_BY_TEN
    B DIVIDE
    
ONE_SIGN 
    LDR R0,=0    
    CMP R1,R2
    BLT PLOT
    
SUBSTRACT
    SUBS R1,R2
    ADDS R0,#1
    CMP R1,R2
    BHS SUBSTRACT    
    
PLOT
    ADDS R0,#48
    BL UART_PUTCHAR
    
    BL DIVIDE_BY_TEN
    CMP R2,#0
    BNE ONE_SIGN

EXIT
    
    POP {R0,R2,PC}
    ENDP    
;********************************************

;********************************************
;* Function:    DIVIDE_BY_TEN
;* Brief:       
;* Input:       R2
;* Output:      R2
;********************************************
DIVIDE_BY_TEN PROC
    PUSH {R1,R3,R4, LR}
    ;R1 10X R4 = 10 R3 
    LDR R3,=0
    LDR R4,=1  
    CMP R2,R4;AK JE CISLO 1, VYNULUJ HO
    BEQ FINITO
    
    LDR R1,=10;10X VACSIE AKO R3
    LDR R4,=10;KONSTANTA
    LDR R3,=1

DIVISION_LOOP

    CMP R2,R1;
    BEQ FINITO
    MULS R1,R4,R1
    MULS R3,R4,R3
    B DIVISION_LOOP
    
FINITO    
    MOVS R2,R3
    
    POP {R1,R3,R4,PC}
    ENDP    
;********************************************

;********************************************
;* Function:    PRINT_HEXA
;* Brief:       
;* Input:       R1
;* Output:      
;********************************************
PRINT_HEXA PROC
    ;R0 je uz ten znak
    ;r1 je input
    ;r2 je pocek o ktory posuvame doprava
    ;r3 je pocet o ktory posuvame dolava
    ;r4 je vydelene cislo
    ;R5 JE CISLO OD 1 DO 8
    PUSH {R0,R1,R2,R3,R4,R5,LR}
    
    LDR R0, ='0'
    BL UART_PUTCHAR
    LDR R0, ='x'
    BL UART_PUTCHAR 
    
    CMP R1,#0
    BNE NONZERO 
    LDR R0, ='0'
    BL UART_PUTCHAR
    B END_OF_FUNCTION      

NONZERO      
    
    LDR R2, =0;PRVE NENULOVE CISLO HO ZMENI
    LDR R3, =0
    LDR R5, =8
    
AGAIN
    
    LDR R0, =0
    SUBS R5, #1
    
    MOVS R4, R1
    LSLS R4, R4,R3
    LSRS R4, R4, #28
 
    CMP R4,#0
    BEQ NOT_YET_PRINTING
    LDR R2, =1    

NOT_YET_PRINTING

    CMP R4,#10
    BLT NUMBER

;SIGN
    ADDS R0, #7
NUMBER
    ADDS R0, #48
    
    ADDS R0,R4

    CMP R2,#0
    BEQ SKIP_PRINTING
    
    BL UART_PUTCHAR
    
SKIP_PRINTING
    ADDS R3, #4
    
    
    CMP R5,#0
    BNE AGAIN

END_OF_FUNCTION

    
    POP {R0,R1,R2,R3,R4,R5,PC}
    ENDP    
;********************************************



    ALIGN
    END