Cross-Platform Low-Level Language

1. Cross-Platform Low-Level Language CPL3 - Language Overview Brian Westphal

2. Design Overview • Designed to be like assembly, except with structure • Designed to be compatible as an intermediate language between many types of high level languages and Assembly • Designed to be cross-platform compatible

3. Design Overview • Supports: • Nested functions • Variable scoping - global, local (per function level) • Very strict typing • One-dimensional arrays • Function pointers • All whitespace can be removed

4. Extended Design Overview • Supports • Dynamic memory allocation/deallocation • No deallocation is available with SPIM • I/O with stdin and stdout

5. Grammar Overview • Given in EBNF format, compatible with my parser generator (available at http://www.fokno.org/parser/) • Written in Java

6. Grammar Overview • In the grammar file, instead of Rule : ‘a’ B ; B : ‘b’ B | ; • There would be Rule ::= ‘a’ B* B ::= ‘b’

7. Grammar Overview • Regular expressions are in single-quotes • There is no need for a separate scanner • Rules are not in single-quotes • Rules can be followed by modifiers: *, +, ? • Other EBNF options are available but not used in this grammar (there are no epsilons or binary subtractions)

8. Grammar Overview • Code can only exist in blocks immediately following a rule: //Supports types for casting and declarations. Type ::= '/(' (IntType | FloatType | CharType | AddressType) '/)' { RETree syntaxTree = (RETree) args; RETree type = (RETree) syntaxTree.get (1); return type.collapse (); }

9. Grammar Overview • The first two sections (sections are denoted by <%>) are for import statements, and additional functions respectively. The third section is for productions. • Other than those things, if you cannot read part of the grammar file, ask me - westphal@cs.unr.edu (and give me 12 to 24 hours to reply) • If you have suggestions for making CPL3 better, (i.e. more complete) please send me email as well.

10. Language Overview -by example: variables vars:; .func_main { return:(i); params:; vars:(i32)$x,(i32)$y; MOV $x (i32)100; MOV $y (i32)0; ADD $y $y $x; RET (i)0; }

11. Language Overview -by example: functions vars:; #This is a comment .func_main { return:(i); params:; vars:(i32)$fact; func_types:((i32):i32); MOV $1 (i32)5; CALL .func_factorial; MOV $fact $return; }

12. Language Overview -by example: functions .func_factorial { return:(i32); params:(i32)$value; vars:(i32)$t1; if $value == (i32)0 { RET (i32)1; }

13. Language Overview -by example: functions else { SUB $t1 $value (i32)1; func_types:((i32):i32); MOV $1 $t1; CALL .func_factorial; MOV $t1 $return; MULT $t1 $t1 $value; RET $t1; } }

14. Language Overview -by example: dynamic memory vars:; .func_main { return:(i); params:; vars:(f32*)$floatArray,(i32)$index; ALLOC $floatArray (i32)100 sizeof(f32); MOV $index (i32)0;

15. Language Overview -by example: dynamic memory wloop $index < (i32)100 { MOV $floatArray[$index] (f32)0.0; ADD $index $index (i32)1; } DEALLOC $floatArray; RET (i)0; }

16. Language Overview -by example: nested functions vars:; .func_main { return:(i); params:; vars:(i)$x; .localfunc_increment { return:void; params:(i)$y; vars:;

17. Language Overview -by example: nested functions ADD $x $x $y; } func_types:((i):i); MOV $1 (i)10; CALL .localfunc_increment; RET (i)0; }

18. Language Overview -by example: function pointers vars:; .func_squareNum { return:(i); params:(i)$x; vars:(i)$y; MULT $y $x $x; RET $y; }

19. Language Overview -by example: function pointers .func_main { return:(i); params:; vars:(i)$x,(void*)$funcPointer; MOV $x (i)10; MOV $funcPointer .func_squareNum;

20. Language Overview -by example: function pointers func_types:((i):i); MOV $1 $x; CALL $funcPointer; MOV $x $return; RET (i)0; }

21. //Signed int types. typedef int i; typedef char i8; typedef short i16; typedef int i32; typedef long long i64; typedef i si; typedef i8 si8; typedef i16 si16; typedef i32 si32; typedef i64 si64; //Unsigned int types. typedef unsigned int ui; typedef unsigned char ui8; typedef unsigned short ui16; typedef unsigned int ui32; typedef unsigned long long ui64; //Signed float types. typedef float f; typedef float f32; typedef double f64; typedef f sf; typedef f32 sf32; typedef f64 sf64; //Unsigned float types (no unsigned float in PowerPC or Intel). typedef float uf; typedef float uf32; typedef double uf64; //Char types. typedef char c; typedef char c8; typedef short c16; Language Overview - types

22. Language Overview -variable and type examples (i32)$x (i32)10 (i32)-10E6 (f32)$pi (f32)3.1415927 (f32)1.0E-6 (c)$letter (c)’a’ (c16)0020 (i*)$pointer (c8*)a0000:B800 (c8)$string[1024]

23. Language Overview - strings • Supported with the MOV statement only MOV $string “Hello World!\n\n”

24. Language Overview - conditions • Conditions do not use parentheses • No complex conditions are allowed (i.e. no &&) • The following operations are allowed: <, <=, ==, >=, >, !=

25. Math: ADD, SUB, MULT, DIV, REM, NEG Logical: EQ, GT, GE, LT, LE, NE, AND, NOT, NOR, OR, XOR Bitwise: SHL, SHR, BAND, BOR, BXOR Functions: RET, CALL Branching: JMP, JEZ Memory: ALLOC, DEALLOC Other: MOV, HALT Language Overview -built-in functions

26. Language Extensions - I/O • The following I/O functions are available via the blackbox programs PrintInt ReadInt PrintFloat ReadFloat PrintDouble ReadDouble PrintString ReadString

27. func_types:(void:i32); MOV $1 (i32)100; CALL .PrintInt; MOV $storage “Hello, World!\n\n” func_types:(void:c8*); MOV $1 $storage; CALL .PrintString; func_types:((i32):void); CALL .ReadInt; MOV $storage $return; func_types:(void:c8*,i32); MOV $1 $storage; MOV $1 (i32)1024; CALL .ReadString; Language Extensions -by example: I/O

28. Blackbox Programs • Use the blackbox programs (available at http://www.fokno.org/cpl3/) to convert your CPL3 code into an executable or into SPIM assembly. • Will only say - error or no errors, no specific error messages • Read the documentation; some things that the compiler allows for are not allowed in the language.

29. Language References • Please see the language reference available at http://www.fokno.org/cpl3/ for additional information and examples. This presentation and example files for this presentation will also be posted on that site. • Also, be sure to see the rest of the links from http://www.fokno.org/ for information on my Java parser and regular expression packages.

30. Comments and Questions • Please feel free to ask any additional questions and make any comments at this time