While at RIT my Computer Science 4 project was a simulation of a simple operating system with that compiler.  A compiler 
and simulator were created. The code that the compiler could interpret was similar to basic. The simulator would run the 
assembly that the compiler generated.
Here is an example of some of the code that the compiler had to understand:
0 let x = 10
10 let x = x * 10
20 let x = 10 * x
30 print x
99 end
I normally wouldn't put up school assignment, but I was proud of the compile that I created.  We only had four weeks to 
complete the entire project (which consisted of many smaller components including the compiler). This gave us maybe a 
week to actually code the compiler. Out of the forty or so groups only two finished (include mine of course). The 
biggest problem for most groups beyond simply coding the compiler was trying to debug the compiler to make sure it was 
generating correct output.
Each generated assembly statement such as <code>2098</code> contained two pieces of information. The action (in this 
case 20 = LOAD) and what to perform it on (in this case slot 98 in memory). Attempting to decider the generated assembly 
in our heads quickly became annoying and time consuming. I modified my compiler to generate smart comments to go with 
the assembly so that the output could quickly and easily be read and debugged. There were a number of other features in 
the compiler above and beyond the original project requirements, but it was this feature which made me keep the code and 
post it here.
Here is a sample output of the above code generated by the compiler with smart debug turned on:
Staring ASM output.
     ; Smada Instruction: let x = 10
     ;     Expression Starting.
2098 ; 0: Load Num: 10
     ;     Expression Ending.
2199 ; 1: let x = Expression (now in the register).
     ; Smada Instruction: let x = x * 10
     ;     Expression Starting.
2099 ; 2: Load variable: x
3398 ; 3: Register * 10
     ;     Expression Ending.
2199 ; 4: let x = Expression (now in the register).
     ; Smada Instruction: let x = 10 * x
     ;     Expression Starting.
2098 ; 5: Load Num: 10
3399 ; 6: Register * x
     ;     Expression Ending.
2199 ; 7: let x = Expression (now in the register).
     ; Smada Instruction: print x
     ;     Expression Starting.
2099 ; 8: Load variable: x
     ;     Expression Ending.
2197 ; 9: Store the register in temporary.
1197 ; 10: Print out the above expression (saved in temporary).
     ; Smada Instruction: end
4300 ; 11: End
.
..
...
..
.
     ; Variables Start.
0    ; Location: 97, Temporary Variable
10   ; Location: 98, Fixed Value.
0    ; Location: 99, Variable: x
     ; Variables End.
There are two components that are included with the source.  smada is a compiler and smadatron can execute binaries 
created by smada.  Use qmake to create the makefiles.