Triangular Numbers using LMC

triangular-number-10A triangular number correspond to the number of dots that would appear in an equilateral triangle when using a basic triangular pattern to build the triangule.

The triangular numbers sequence contains all the triangular numbers in order.

The first 10 numbers of the triangular number sequence are:

1, 3, 6, 10, 15, 21, 28, 36, 45, 55, …

trinagular-number-sequence

The following table shows how we can calculate each triangular number from this sequence:

Triangular Number Calculation
1 =1
3 =1+2
6 =1+2+3
10 =1+2+3+4
15 =1+2+3+4+5

Little Man Computer


Your challenge is to write a program using the Online LMC Simulator to calculate and output the first 10 triangular numbers of this sequence.

LMC Instruction Set


Note that in the following table “xx” refers to a memory address (aka mailbox) in the RAM. The online LMC simulator has 100 different mailboxes in the RAM ranging from 00 to 99.

Mnemonic Name Description Op Code
INP INPUT Retrieve user input and stores it in the accumulator. 901
OUT OUTPUT Output the value stored in the accumulator. 902
LDA LOAD Load the Accumulator with the contents of the memory address given. 5xx
STA STORE Store the value in the Accumulator in the memory address given. 3xx
ADD ADD Add the contents of the memory address to the Accumulator 1xx
SUB SUBTRACT Subtract the contents of the memory address from the Accumulator 2xx
BRP BRANCH IF POSITIVE Branch/Jump to the address given if the Accumulator is zero or positive. 8xx
BRZ BRANCH IF ZERO Branch/Jump to the address given if the Accumulator is zero. 7xx
BRA BRANCH ALWAYS Branch/Jump to the address given. 6xx
HLT HALT Stop the code 000
DAT DATA LOCATION Used to associate a label to a free memory address. An optional value can also be used to be stored at the memory address.

Solution


The following Assembly/LMC code provides a good example of how branching (e.g BRP instruction) can be used to create a loop (iteration).
iteration-label

Did you know?


In the code above, loop, counter, numbers, one and ten are called labels. ADD, OUT, STA, LDA, BRP, SUB, HLT, DAT are the mnemonics, each of them representing the opcode of an instruction.

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