Housework:īefore we write down the Machine Code, we should think about how to achieve this goal by pseudo code.
#Nand to tetris screen code
Output is effected by writing code that manipulates the screen memory map. The physical display is continuously refreshed from the memory map,many times per second. Keyboard:The interfaces between computer and keyboard are located in RAM address 24576(0圆000).Whenever a key is pressed on the physical keyboard,its 16-bit ASCII code appears in RAM.When no key is pressed,the code 0 appears in this location.In the addition to the usual ASCII codes,the Hack keyboard recognizes the keys shown in the following picture.Ī designated memory area,dedicated to manage a display unit.
The corresponding bit in the RAM-resident memory map:1 = black,0 = white.Ģ.Set the(col%16)th bit of word to 0 or 1. You will be starting to build computer from basic unit of any device, Nand gate.
#Nand to tetris screen software
The course comes with a book, software and source code to build things on your computer.Watch this video to get complete understanding of the course. Screen :the screen's contents are starts at RAM address 16384(0x4000). Nand to Tetris is a free course to build computer from first principles. Now we can use Hack Language to multiply two numbers and then store them in a specific register. Jump:specify a jump condition,namely,which command to fetch and execute next
The leftmost bit is the C-instruction code,which is 1.The next two bits are not used.The remaining bits form three fields that correspond to the three parts of the instruction's symbolic representation.ĭest:where to store the computed value(ALU output) Check it out: Review of From NAND to Tetris in 12 Steps. The C-Instruction dest = comp jump //Either the dest or jump fields may be empty.If dest is empty,the "=" is ommitted.If jump is empty,the " "is omitted. I wrote out all the key ideas from this video lecture in one of my posts. The A-Instruction //where value is either a non-negative decimal number or a symbol referring to sum number. M register:refer to the memory word whose address is the current value of the A register.(M stands for Memory) the specified value in the A register.įor example,if I set means the effect is that setting the A register to 21,and also RAMbecomes the selected RAM register.Īctually,the Hack language consists of two generic instructions: an address instruction,also called A-instruction,and a compute instruction,also called C-instruction.Each instruction has a binary representation. Memory Address Spaces:ĭ register:only can be used to store data valuesĪ register:can be interpreted either as a data value or as an address in the data memory,or as an address in the instruction memory. The hack computer is a 16-bit machine,consisting of a CPU,two separate memory modules serving as instuction memory and data memory,and two memory-mapped I/O devices:a screen and a keyboard.
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