Nand2Tetris Screen Addressing

http://www.nand2tetris.org/lectures/PDF/lecture%2005%20computer%20architecture.pdf

So, you have 256 rows each 1 pixel thick.
You have 32 columns each 16 bits thick, or 512 columns, each 1 pixel thick.

So, to set pixel at x,y where x,y within (0-511, 0-255) :

Set (black) the y % 16 bit of the word addressed by Screen[ x*32 + y/16]

where Screen[X] implies memory address 16384 + X.

Nand2Tetris Hack Language Min Function

Make a more efficient mult:)

// finds min of R0 and R1 and stores the result in R2.
// (R0, R1, R2 refer to RAM[0], RAM[1], and RAM[2], respectively.)

// how : start off assuming R0 is smaller. Then, subtract R1 from R0 and, if 
// result is > 0 => R1 is smaller, put R1 in R2.

@R0
D=M
@R2
M=D // until we find that R1 is smaller
@R1
D=M
@R0
M=M-D // we have R0 - R1
@R0 // if > 0, then we need to put R1 in R2
D=M
@R1SMALLER
D, JGT // if R1 is smaller than R0, this will be > 0 ..
@END
0, JMP // else, we're done

(R1SMALLER)
@R1
D=M
@R2
M=D

(END)
@END
0, JMP

nand2tetris Hilf Help Shimon!

I load a program into the CPU emulator and nothing happens.

Might need to drag the lower right corners south-east a little to see the status line - you'll probably see a message there. Why the hell they don't have a View > Parser Log through the Menu just beats me. But hey, it's free :)

I do

@LOOP
JMP

and it doesn't like it. Ya, coz you HAVE to supply the core part of a C (compute) instruction always - only the jump and destination are optional. So, in this case, just do

0, JMP

Better nand2tetris. Please Shimon. Please Yaron.

In script ... illegal terminator '}' -- when your code doesn't even contain that character on that line. This happens when you run the HDLsimulator from the command line and give it an HDL file rather than a test script.

Why not provide an intelligent error message - ATLO perl saying ". Missing semicolon on previous line?" You get the idea..

Also, support for underscores would be nice. Duh :)

Nand2Tetris C Instruction Cheat Sheet

Screen : 256 rows of 32 16-bit words each (512 pixel columns)

Qualcomm Snapdragon Boot Android

Can you use a bluetooth mouse/keyboard combo? Yes - something like the Logitech MK700/M705 work fine.
Do you *have* to use a true HDMI cable (no HDMI/VGA adapter allowed)? Yes (I know, shame on Q - R-Pi can do this)

Shame on You Qualcomm! Dragonboard <<<< Raspberry Pi

http://www.96boards.org/forums/topic/dragonboard-410c-support-for-off-the-shelf-hdmi-to-vga-converters/#post-10330