to write a robotic arm controller. The controller has one motor for each of the five fingers $($the pinky is finger $0$ and the thumb is finger $4,$ with others in order$).$ Our hardware uses a scheme called memory$-$mapped I$/$O$,$ whereby the hardware intercepts accesses to particular memory locations and interprets them as signals to the hardware device instead of RAM accesses $($thus$,$ these addresses do not correspond to reads$/$writes of memory, which might not even exist at these addresses$).$

Arm User's Guide

The arm's API supports the following operations $($and more$)$:

$$Initialize: write the integer $0$ to memory location $0$xFFEE$5678$ This will also close all fingers com$-$ pletely.

$$Ready: Every initialization operation must be followed by this $($once$)$ to ensure that the arm is ready to receive commands. The arm clears bit $7$ of memory location $0$xFFEE$5678$ after it has initialized all its motors and it is ready to receive instructions. In other words, the program must wait for this bit to become $1$ before proceeding.

$$Open finger k by $\mathrm{.}01$ radians: set bit k $(0<=$k $<=4)$ of memory location $0$xFFEE$567$C The upper $16$ bits $($i$.$e$.,$ k $>=16)$ do not map to any I$/0$ devices $($and may thus be corrupted as you wish$).$

$$Close finger k by $\mathrm{.}01$ radians: set bit k$+5(0<=$ k $<=4)$ of memory location

$0$xFFEE$567$C$.$

Due to mechanical issues $($since motors are far slower than computers$),$ successive openings of the same finger must be separated by at least $2$ ms$.,$ to avoid motor slippage.

Assignment

Draw a CFG and write a MIPS program to do the following:

$$Open the index finger completely $($i$.$e$.,3\mathrm{.}14$ radians$)$

$$Close the index finger exactly half way while opening the thumb also exactly half way. You wish to do these two fingers in interspersed manner, not one after the other $-$ in other words, this means you should close the index finger by $\mathrm{.}01$ radians, then open the thumb by $\mathrm{.}01$ radians, before closing the index finger more.

Since we don't yet have a way to implement time delays, you can simply write delay n as an instruction to indicate a delay of n $$s$..$

The same conventions$/$rules as on the previous homework apply, but you may also use the pseudoinstructio li if you want, and of course the branch$-$related instructions $($but not pseudoinstructions$).$ Submissions without a CFG will not be graded $($and it makes no sense to not do the CFG first$).$