ARM ASSEMBLY: 1.)Using the code from sub_demo.s, update the PrintString subroutine so that it prints an end of line character at the end of the string it sends to the UART. (Reminder: the enter character is 0x0A.

/* ------------------------------------------------------- sub_demo.s Demonstrates the use of a subroutine to print to the UART. ------------------------------------------------------- */ .org 0x1000 // Start at memory location 1000 .text // Code section .global _start _start: LDR R4, =First BL PrintString LDR R4, =Second BL PrintString LDR R4, =Third BL PrintString LDR R4, =Last BL PrintString _stop: B _stop // Subroutine constants .equ UART_BASE, 0xff201000 // UART base address PrintString: /* ------------------------------------------------------- Prints a null terminated string. ------------------------------------------------------- Parameters: R4 - address of string Uses: R0 - holds character to print R1 - address of UART ------------------------------------------------------- */ STMFD SP!, {R0-R1, R4, LR} LDR R1, =UART_BASE psLOOP: LDRB R0, [R4], #1 // load a single byte from the string CMP R0, #0 BEQ _PrintString // stop when the null character is found STR R0, [R1] // copy the character to the UART DATA field B psLOOP _PrintString: LDMFD SP!, {R0-R1, R4, PC} .data .align // The list of strings First: .asciz "First string" Second: .asciz "Second string" Third: .asciz "Third string" Last: .asciz "Last string" _Last: // End of list address .end