2.2 2.3 - lab 2: introduction to assembly language

Formulate instructions to do the following things:

• Set bit 3 to 1 at the memory address 0xd640 while leave bits 0-2 and 4-16 unaffected.
• Jump to the instruction labeled POINT if the carry bit is set.
• Shift register R6 right one place while preserving the sign.

Examine this loop: ... more instructions... Mov.w&I, R4 Cmp.w #0x0000, R4JZ After_loop Start_loop:Dec.w #0x0001, R4 JZ After_loopBR #Start_loop After_loop:...more instructions...

• How many times will this loop execute?
• Why do we use the BR instruction with a #Start_loop, but with the JZ we use a plain After_loop?
• What does the first JZ instruction do? If we did not have this initial Cmp and JZ, what (possibly) inadvertent effect might occur?

Re-write the blinking light program from Lab 1 using assembly code instead. As you may recall, the program must blink "SOS" (which is "... --- ...") and conform to the following Morse Code standards:

• The ammount of time of a dash is equivalent in length to 3 dots.
• The ammount of time between parts of a letter is equivalent in length to one dot.
• The ammount of time between letters is equivalent in length to 3 dots.
• The ammount of time between words (assume each SOS is a word) is equivalent to 5 dots.