OAM Assembly Language clarification

Question

I am having trouble writing an OAM program that generates a sequence of odd numbers with alternating signs starting with 1.

I have written a program but it does not work and I am not sure why. Because this is a rare language if anyone can help and explain what I am doing wrong that would be great.

X,NOOP
Y,NOOP 
LDA stdin
loop, SET 1
LDA Y
STA 0
LDA X
DEC
STA X #X = X - 1
LDA X #ACC = X

Answer 1

Note for other readers wondering what the heck this is all about:
an webbased One Address Machine compiler/assembler/emulator called OAMulator is here .

You ask for an OAM program that generates a sequence of odd numbers with alternating signs starting with 1 (without specifying the max value).
I'll interpret that you want the following output: 1, -3, 5, -7, 9, -11, 13, -15 etc... .

I assume your LDA stdin is meant to ask for the max value, but you don't seem to store it with STA . Also you didn't start with branching ( BR ) to the 'program block' after initializing the your variables x and y . I also don't really see how your code is going to alternate sign...

I cheated by first writing the OAMPL code:

n = 1                       #Init number n as 1
PRINT "enter max number:"   #Ask for max number
READ i                      #Read that number from input, storing it as i
LOOP (/ i 2)                #Calculate number of iterations, passing that to LOOP
  IF t                      #If t (toggle)
    t = 0                   #Toggle falsy
    PRINT (- 0 n)           #Print 0-counter
  ELSE
    t = 1                   #Toggle truthy
    PRINT n                 #Print counter
  ENDIF
  n = (+ n 2)               #Increase counter by 2
END
EXIT                        #Exit program

that will compile to the following OAM Assembly :

# Emitted by the OAMPL compiler
1.  BR  5   # branch to program block
# Variable storage allocation block
2. n,   NOOP    # variable n
3. i,   NOOP    # variable i
4. t,   NOOP    # variable t
# Begin OAM program block
# OAMPL: n = 1
5.  SET 1
6.  STA n
# OAMPL: PRINT "enter max number:"
7.  SET "enter max number:"
8.  STA stdout
# OAMPL: READ i
9.  LDA stdin
10. STA i
# OAMPL: LOOP (/ i 2)
11. SET 2
12. STA 14
13. BR 15
14. NOOP    # intermediate value
15. LDA i
16. DIV 14
17. BR L18
18. NOOP    # loop counter
# OAMPL: IF t
19. LDA t
20. BRZ I20
# OAMPL: t = 0
21. SET 0
22. STA t
# OAMPL: PRINT (- 0 n)
23. LDA n
24. STA 26
25. BR 27
26. NOOP    # intermediate value
27. SET 0
28. SUB 26
29. STA stdout
# OAMPL: ELSE
30. BR I30
31. I20,    NOOP
# OAMPL: t = 1
32. SET 1
33. STA t
# OAMPL: PRINT n
34. LDA n
35. STA stdout
# OAMPL: ENDIF
36. I30,    NOOP
# OAMPL: n = (+ n 2)
37. SET 2
38. STA 40
39. BR 41
40. NOOP    # intermediate value
41. LDA n
42. ADD 40
43. STA n
# OAMPL: END
44. LDA 18
45. DEC
46. L18,    STA 18
47. BRP 19
# OAMPL: EXIT
48. HLT

Note: you can also leave out the comments ( # comment ) and leading (line-) numbering.

If I enter 50 in the input -field (to answer the max value question) and hit execute (after compiling!), I get the following output result:

enter max number:
1
-3
5
-7
9
-11
13
-15
17
-19
21
-23
25
-27
29

Hope this helps!