Intermediate Annotated DataType for extended M
(vanilla M is basically the same, minus the array descriptions, case statement, and I_REF, I_SIZE operators. It also removes the character and real datatypes) functions, number of local variables, array descriptions, body. data I_prog = I_PROG ([I_fbody],Int,[(Int,[I_expr])],[I_stmt]) function label, local functions, number of local variables, number of arguments array descriptions, body data I_fbody = I_FUN (String,[I_fbody],Int,Int,[(Int,[I_expr])],[I_stmt]) level, offset, array indexes, expressions data I_stmt = I_ASS (Int,Int,[I_expr],I_expr) while loop: expression, statement | I_WHILE (I_expr,I_stmt) If statement: condition expression, statement to execute if true, statement to execute if false | I_COND (I_expr,I_stmt,I_stmt) Case statement for custom data type. Expression, [constructor #, # of arguments to constructor, statement to execute] | I_CASE (I_expr,[(Int,Int,I_stmt)]) Read various types of variables (level, offset, array indexes) | I_READ_B (Int,Int,[I_expr]) | I_READ_I (Int,Int,[I_expr]) | I_READ_F (Int,Int,[I_expr]) | I_READ_C (Int,Int,[I_expr]) Print out values of various types (expression) | I_PRINT_B I_expr | I_PRINT_I I_expr | I_PRINT_F I_expr | I_PRINT_C I_expr | I_RETURN I_expr a block: functions, number of local variables, array descriptions, body. | I_BLOCK ([I_fbody],Int,[(Int,[I_expr]))],[I_stmt])
Values of different base types 1 of 8
Values of different base types data I_expr = I_IVAL Int | I_RVAL Float | I_BVAL Bool | I_CVAL Char Identifier: level offset, array indexes | I_ID (Int,Int,[I_expr]) Apply some operation... expressions as parameters | I_APP (I_opn,[I_expr]) A reference to an array (to pass) level, offset | I_REF (Int,Int) request the size of an array dimension: level,offset,dimension | I_SIZE (Int,Int,Int) Function Call: label and level data I_opn = I_CALL (String,Int) constructor number and number of arguments | I_CONS (Int,Int) Arithmetic operators for integers and floats | I_ADD_I | I_MUL_I | I_SUB_I | I_DIV_I | I_NEG_I | I_ADD_F | I_MUL_F | I_SUB_F | I_DIV_F | I_NEG_F comparison operators for various types | I_LT_I | I_LE_I | I_GT_I | I_GE_I | I_EQ_I | I_LT_F | I_LE_F | I_GT_F | I_GE_F | I_EQ_F | I_LT_C | I_LE_C | I_GT_C | I_GE_C | I_EQ_C logical connectives | I_NOT | I_AND | I_OR type casting: (integer > float, float > integer, float >integer) | I_FLOAT | I_FLOOR | I_CEIL
Intermediate code example
2 of 8
Intermediate code example Original source code:
/* Fibonacci ... */ var n:int fun fib(n:int):int {var z:int begin if n =< 1 then z:= 1 else z:= fib(n 1) + fib(n 2) return z end} begin read n print fib(n) end
Abstract Syntax Tree:
M_prog ( [ M_var ("n",[],M_int), M_fun ("fib", [("n",0,M_int)], M_int, [M_var ("z",[],M_int)], [M_cond (M_app (M_le,[M_id ("n",[]),M_ival 1]), M_ass ("z",[],M_ival 1), M_ass ("z",[], M_app (M_add, [M_app (M_fn "fib",[M_app (M_sub,[M_id (" n" , []),M_ival 1])]), M_app (M_fn "fib",[M_app (M_sub,[M_id ("n",[]), M_ival 2])])]))), M_return (M_id ("z",[])) ]) ], [M_read ("n",[]), M_print (M_app (M_fn "fib",[M_id ("n",[])]))])
Symbol Table (when trying to generate code for the recursive call):
3 of 8
Symbol Table (when trying to generate code for the recursive call):
[ symbol_table 1, ( 1, [var (n, int, 4), var (z, int, 1) ]), symbol_table (1, 0, [var (n, int, 1), func (fib, int, [int], code_label_fib_1319)])]
Intermediate Representation:
I_PR OG ( [I_FUN (code_label_fib_1319, [], 1, 1, [], [ statements I_APP (I_LE_I, [I_ID (0, 4, []), I_IVAL 1]), I_ASS (0, 1, [], I_IVAL 1), I_ASS (0, 1, [], I_APP (I_ADD, [ I_APP( I_CALL (code_label_fib_1319, 1), [I_A PP (I_S UB_I, [I_ID (0, 4, []), I_INT 1]), I_APP( I_CALL (code_label_fib_1319, 1), [I_A PP (I_S UB_I, [I_ID (0, 4, []), I_INT 2]) ] RETURN (I_ID (0, 1, []) ]) ], 1, [], [ I_READ_I (0, 1, []), I_PRINT_I (I_APP (I_CALL (code_label_fib_1319, 0), I_ID (0, 1, []))) ] ) I_COND (
AM Stack Machine Code
4 of 8
AM Stack Machine Code
% Note that I used the code label from the % sample symbol table you' d end up % with a label number other than 1319 % Setup storage for main LOAD _R %sp LOAD _R %sp STOR E_R %fp ALLO C 1 % S etup deallocation counter LOAD _I 3 % read(n) READ _I LOAD _R %fp STOR E_O 1 % setup caller portion of activation record for fib LOAD _R %fp LOAD _O 1 ALLO C 1 LOAD _R %fp LOAD _R %fp LOAD _R %cp JUMP code_label_fib_1319 % print the resulting value PRINT _I % use deallocation counter to free used storage LOAD _R %fp LOAD _O 2 ALLO C_S % program is done HALT code_label_fib_1319: % S etup frame pointer LOAD _R %sp STOR E_R %fp % A llocate local variable storage ALLO C 1 % this line and the next setup the frame pointer
5 of 8
% S etup deallocation counter LOAD _I 2 % first part of the if statement: % test N <= 1 LOAD _R %fp LOAD _O 4 LOAD _I 1 APP L E % jump to else clause if test fails JUMP _C labelelse % z := 1 LOAD _I 1 LOAD _R %fp STOR E_O 1 % jump to end of if statement JUMP endofif labelelse: % N eed to add tw o values together to determine % new value of z % calculate fib(n 1) LOAD _R %fp LOAD _O 4 LOAD _I 1 APP S UB ALLO C 1 LOAD _R %fp % note that for both recursive calls w e % need to follow the static link back % once to find our environment LOAD _R %fp LOAD _O 1 LOAD _R %cp JUMP code_label_fib_1319 % calculate fib(n 2) ...