Edinburgh IMP77 Compiler - Version 8.4 1 %begin NO_APP .Ltext0: .section .rodata .LC0: .byte 40 .string "Imp77 precedence and associativity test." .zero 214 .LC11: .byte 85 .string "a * b // c * d is left associative and with equal precedence, i.e. ((a * b) // c) * d" .zero 169 .LC7: .byte 37 .string "This grammar would support the above:" .zero 217 .LC12: .byte 33 .string "P = ;" .zero 221 .LC13: .byte 46 .string "P = | ;" .zero 208 .LC14: .byte 26 .string "P = ;" .zero 228 .LC20: .byte 51 .string "p ^^ q ^^ r is left associative, i.e. (p ^^ q) ^^ r" .zero 203 .LC21: .byte 34 .string "P = ;" .zero 220 .LC22: .byte 49 .string "P = | ;" .zero 205 .LC23: .byte 27 .string "P = \"^^\" ;" .zero 227 .align 2 .globl main main: .LFB185: .LVL0: link.w %fp,#-5632 movem.l #15928,-(%sp) 2 move.l 12(%fp),-(%sp) move.l 8(%fp),-(%sp) jsr _imp_initialise .LVL1: .LBB171: 3 ! 4 ! Precedence of operators 5 ! 6 ! Highest: 1. \ (complement, unary not) 7 ! 2. \, \\, <<, >> 8 ! 3. *, /, //, & 9 ! Lowest: 4. +, - (unary and binary), !, !! 10 ! 11 ! In general, sub-expressions with operators of equal precedence are evaluated from left to right. 12 ! 13 ! The one exception to the left-hand precedence rule is that consecutive 14 ! exponentiations are evaluated from right to left; thus A**B**C is 15 ! evaluated as A**(B**C), not as (A**B)**C. (Imp80 documentation) 16 17 ! Arithmetic operators: 18 19 ! |...| modulus also: !...! (deprecated some time ago) 20 21 ! ! inclusive or 22 ! !! exclusive or 23 ! & and 24 25 ! \ real exponentiation also: ^ (Imp77) or ** (ERCC compilers) 26 ! \\ integer exponentiation also: ^^ (Imp77) or **** 27 28 ! * multiply 29 ! / real division 30 ! // integer division 31 32 ! << left shift 33 ! >> right shift 34 35 ! + plus 36 ! - minus 37 38 ! + unary + 39 ! - unary - 40 ! \ unary not also ~ (can be *displayed* as: ¬ (¬)) 41 42 ! . string concatenation 43 44 ! Comparison operators: 45 ! = eq 46 ! # not equals also \= and <> (Imp80 documentation) 47 ! == address equals 48 ! ## address not equals also \== 49 ! -> string resolution (a difficult to classify hybrid of a comparison and an assignment operator) 50 ! <= less than or equals 51 ! < less than 52 ! >= greater than or equals 53 ! > 54 55 ! Assignment operators: 56 ! = assignment 57 ! == pointer assignment 58 ! <- jam transfer 59 ! -> string resolution 60 61 ! Data structure operators: 62 ! _ record field 63 ! () array indexing 64 ! [] pointer increment (a Hamish extension in 68000 Imp only) 65 66 ! Other: 67 ! @ may be considered an operator in %real literals, usually handled by a BIP. 68 69 70 %const %integer a = 19, b = 17, c = 5, d = 3 71 %integer x = a * b // c * d 72 print string("Imp77 precedence and associativity test."); newlines(2) move.l %fp,%d3 .LVL2: add.l #-256,%d3 .LVL3: move.l #256,%d2 move.l %d2,-(%sp) pea .LC0 move.l %d3,-(%sp) lea memcpy,%a2 jsr (%a2) .LVL4: move.l %fp,%d5 .LVL5: add.l #-5632,%d5 .LVL6: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL7: move.l %fp,%d4 .LVL8: add.l #-2816,%d4 .LVL9: lea (32,%sp),%sp move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL10: .LBE171: .LBB172: .LBB173: lea (-256,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL11: lea (12,%sp),%sp lea _imp_printstring,%a4 jsr (%a4) .LVL12: .LBE173: .LBE172: .LBB174: .LBB175: lea (268,%sp),%sp pea 2.w jsr _imp_newlines .LVL13: .LDL1: .LDL2: .LBE175: .LBE174: .LBB176: 73 %if x = 21 %start 74 print string("In a * b // c * d, '*' has higher priority than '/'."); newline 75 print string("A second test with '/' will be needed to determine associativity:"); newline 76 x = a // c // d 77 %if x = 1 %start 78 print string("a // c // d is right associative, i.e. a // (b // c)"); newline 79 %else %if x = 19 80 print string("a // c // d is left associative, i.e. (a // b) // c"); newline 81 %else 82 print string("a // c // d is something weird! I give up."); newline 83 %finish 84 %else %if x = 19 85 print string("a * b // c * d is right associative and with equal precedence, i.e. a * (b // (c * d))"); newline 86 newline 87 print string("This grammar would support the above:"); newline 88 newline 89 print string("P = ;"); newline 90 print string("P = | ;"); newline 91 print string("P = ;"); newline 92 %else %if x = 192 93 print string("a * b // c * d is left associative and with equal precedence, i.e. ((a * b) // c) * d"); newline move.l %d2,-(%sp) pea .LC11 move.l %d3,-(%sp) jsr (%a2) .LVL14: add.l #256,%d5 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL15: add.l #1280,%d4 .LVL16: move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL17: .LBE176: .LBB177: .LBB178: lea (-216,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL18: lea (12,%sp),%sp jsr (%a4) .LVL19: .LBE178: .LBE177: .LBB179: .LBB180: add.l %d2,%sp lea _imp_newline,%a3 jsr (%a3) .LVL20: .LBE180: .LBE179: .LBB181: .LBB182: jsr (%a3) .LVL21: .LBE182: .LBE181: .LBB183: 94 newline 95 print string("This grammar would support the above:"); newline move.l #.LC7,%d4 .LVL22: move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL23: move.l %fp,%d6 .LVL24: add.l #-5120,%d6 .LVL25: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d6,-(%sp) jsr (%a2) .LVL26: add.l #3584,%d5 move.l %d2,-(%sp) move.l %d6,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL27: .LBE183: .LBB184: .LBB185: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL28: lea (12,%sp),%sp jsr (%a4) .LVL29: .LBE185: .LBE184: .LBB186: .LBB187: add.l %d2,%sp jsr (%a3) .LVL30: .LBE187: .LBE186: .LBB188: .LBB189: jsr (%a3) .LVL31: .LBE189: .LBE188: .LBB190: 96 newline 97 print string("P = ;"); newline move.l %d2,-(%sp) pea .LC12 move.l %d3,-(%sp) jsr (%a2) .LVL32: add.l #256,%d6 .LVL33: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d6,-(%sp) jsr (%a2) .LVL34: add.l #-256,%d5 move.l %d2,-(%sp) move.l %d6,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL35: .LBE190: .LBB191: .LBB192: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL36: lea (12,%sp),%sp jsr (%a4) .LVL37: .LBE192: .LBE191: .LBB193: .LBB194: add.l %d2,%sp jsr (%a3) .LVL38: .LBE194: .LBE193: .LBB195: 98 print string("P = | ;"); newline move.l %d2,-(%sp) pea .LC13 move.l %d3,-(%sp) jsr (%a2) .LVL39: add.l #256,%d6 .LVL40: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d6,-(%sp) jsr (%a2) .LVL41: add.l #-256,%d5 move.l %d2,-(%sp) move.l %d6,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL42: .LBE195: .LBB196: .LBB197: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL43: lea (12,%sp),%sp jsr (%a4) .LVL44: .LBE197: .LBE196: .LBB198: .LBB199: add.l %d2,%sp jsr (%a3) .LVL45: .LBE199: .LBE198: .LBB200: 99 print string("P = ;"); newline move.l %d2,-(%sp) pea .LC14 move.l %d3,-(%sp) jsr (%a2) .LVL46: add.l #256,%d6 .LVL47: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d6,-(%sp) jsr (%a2) .LVL48: add.l #-256,%d5 move.l %d2,-(%sp) move.l %d6,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL49: .LBE200: .LBB201: .LBB202: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL50: lea (12,%sp),%sp jsr (%a4) .LVL51: .LBE202: .LBE201: .LBB203: .LBB204: add.l %d2,%sp jsr (%a3) .LVL52: .LDL3: .LDL4: .LBE204: .LBE203: .LBB205: .LBB206: jsr (%a3) .LVL53: .LDL5: .LBE206: .LBE205: .LBB207: 100 %else 101 print string("a * b // c * d uses some weird non-standard combination of precedence and associativity!"); newline 102 %finish 103 newline 104 105 106 %const %integer p = 4, q = 3, r = 2 107 %integer y 108 109 y = p ^^ q ^^ r 110 111 %if y = 262144 %start 112 print string("p ^^ q ^^ r is right associative, i.e. p ^^ (q ^^ r)"); newline 113 newline 114 print string("This grammar would support the above:"); newline 115 newline 116 print string("P = ;"); newline 117 print string("P = | ;"); newline 118 print string("P = ""^^"" ;"); newline 119 %else %if y = 4096 120 print string("p ^^ q ^^ r is left associative, i.e. (p ^^ q) ^^ r"); newline move.l %d2,-(%sp) pea .LC20 move.l %d3,-(%sp) jsr (%a2) .LVL54: add.l #-1536,%d5 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d5,-(%sp) jsr (%a2) .LVL55: move.l %d2,-(%sp) move.l %d5,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL56: .LBE207: .LBB208: .LBB209: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL57: lea (12,%sp),%sp jsr (%a4) .LVL58: .LBE209: .LBE208: .LBB210: .LBB211: add.l %d2,%sp jsr (%a3) .LVL59: .LBE211: .LBE210: .LBB212: .LBB213: jsr (%a3) .LVL60: .LBE213: .LBE212: .LBB214: 121 newline 122 print string("This grammar would support the above:"); newline add.l #-256,%d3 move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL61: move.l %fp,%d4 .LVL62: add.l #-3840,%d4 .LVL63: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL64: move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL65: .LBE214: .LBB215: .LBB216: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL66: lea (12,%sp),%sp jsr (%a4) .LVL67: .LBE216: .LBE215: .LBB217: .LBB218: add.l %d2,%sp jsr (%a3) .LVL68: .LBE218: .LBE217: .LBB219: .LBB220: jsr (%a3) .LVL69: .LBE220: .LBE219: .LBB221: 123 newline 124 print string("P = ;"); newline add.l #-256,%d3 move.l %d2,-(%sp) pea .LC21 move.l %d3,-(%sp) jsr (%a2) .LVL70: add.l #256,%d4 .LVL71: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL72: move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL73: .LBE221: .LBB222: .LBB223: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL74: lea (12,%sp),%sp jsr (%a4) .LVL75: .LBE223: .LBE222: .LBB224: .LBB225: add.l %d2,%sp jsr (%a3) .LVL76: .LBE225: .LBE224: .LBB226: 125 print string("P = | ;"); newline add.l #-256,%d3 move.l %d2,-(%sp) pea .LC22 move.l %d3,-(%sp) jsr (%a2) .LVL77: add.l #256,%d4 .LVL78: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL79: move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL80: .LBE226: .LBB227: .LBB228: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL81: lea (12,%sp),%sp jsr (%a4) .LVL82: .LBE228: .LBE227: .LBB229: .LBB230: add.l %d2,%sp jsr (%a3) .LVL83: .LBE230: .LBE229: .LBB231: 126 print string("P = ""^^"" ;"); newline add.l #-256,%d3 move.l %d2,-(%sp) pea .LC23 move.l %d3,-(%sp) jsr (%a2) .LVL84: add.l #256,%d4 .LVL85: move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d4,-(%sp) jsr (%a2) .LVL86: move.l %d2,-(%sp) move.l %d4,-(%sp) move.l %d3,-(%sp) jsr (%a2) .LVL87: .LBE231: .LBB232: .LBB233: lea (-220,%sp),%sp move.l %sp,%d0 move.l %d2,-(%sp) move.l %d3,-(%sp) move.l %d0,-(%sp) jsr (%a2) .LVL88: lea (12,%sp),%sp jsr (%a4) .LVL89: .LBE233: .LBE232: .LBB234: .LBB235: add.l %d2,%sp jsr (%a3) .LVL90: .LDL6: .LBE235: .LBE234: .LBB236: .LBB237: jsr (%a3) .LVL91: .LBE237: .LBE236: .LBB238: .LBB239: clr.l -(%sp) jsr exit .LVL92: .LBE239: .LBE238: .LFE185: .Letext0: 127 %else 128 print string("p ^^ q ^^ r is something weird! ("); write(y, 0); print string(") - I give up."); newline 129 %finish 130 newline 131 132 ! The remaining issue to be checked is how left/right associativity interact when the precedence is the same, 133 ! which is only the case for exponentiation and shifts together, eg 134 ! 135 ! a << b << c ^^ d ^^ e or a ^^ b ^^ c >> d >> e 136 ! 137 138 %endofprogram 89 Statements compiled