*decode cond2s Chunk 1 OBJ_HEAD Offset:0000008C Size:00000040 Chunk 2 OBJ_IDFN Offset:000000CC Size:00000018 Chunk 3 OBJ_STRT Offset:000000E4 Size:00000074 Chunk 4 OBJ_SYMT Offset:00000158 Size:00000070 Chunk 5 OBJ_AREA Offset:000001C8 Size:00000154 Chunk 6 OBJ_UNU1 Offset:00000000 Size:00000000 Chunk 7 OBJ_UNU1 Offset:00000000 Size:00000000 Chunk 8 OBJ_UNU1 Offset:00000000 Size:00000000 Area 1 Id:00000000 Attributes:6202 Size:00000108 Relocs:00000008 Base:00000000 Area 2 Id:0000000C Attributes:0002 Size:00000004 Relocs:00000001 Base:00000000 Symbol Table attr:0001 value:0000 Area "$CODEAREA" "$CODEAREA" attr:0001 value:0000 Area "$DATAAREA" "$DATAAREA" attr:0002 value:0000 Area "$DATAAREA" "3L_imp___entry_point" attr:0002 value:0000 Area "$DATAAREA" "3L_IMP___read_i" attr:0002 value:0000 Area "$DATAAREA" "3L_IMP_WRITE" attr:0003 value:0010 Area "$CODEAREA" "3L___main_program" attr:0002 value:0000 Area "$DATAAREA" "3L___cur_out" Code relocations offset:0000 Word PC Relative "3L_imp___entry_point" offset:00CC Word PC Relative "3L_IMP_WRITE" offset:00B8 Word PC Relative "3L_IMP_WRITE" offset:00A4 Word PC Relative "3L_IMP_WRITE" offset:0034 Word PC Relative "3L_IMP___read_i" offset:002C Word PC Relative "3L_IMP___read_i" offset:0024 Word PC Relative "3L_IMP___read_i" offset:000C Word Additive Symbol "$DATAAREA" Data relocations offset:0000 Word Additive Symbol "3L___cur_out" String Table 00000 $CODEAREA 0000C $DATAAREA 00018 3L_imp___entry_point 00030 3L_IMP_WRITE 00040 3L_IMP___read_i 00050 3L___main_program 00064 3L___cur_out Dump of Code Area 1 ! 2 ! The hand-generated code below should be producable by PSR's compiler if it: 3 ! A) delays stores as late as possible 4 ! 5 ! B) remembers registers over procedure calls 6 ! 7 ! C) has a general algorithm for drop-through conditionally executed 8 ! instructions, i.e. if there are no instructions between a conditional 9 ! branch and its destination which set the condition codes, and the 10 ! sequence is less that a certain length, then all the instructions 11 ! within the sequence can be made conditional. 12 ! 13 ! D) does as above, but also allows instructions within the sequence 14 ! whose subsequent execution depends on the same condition, e.g. 15 ! 16 ! %if a=b %and c=d %then a=b 17 ! 18 ! CmpS R0,R1 NAIVE STYLE 19 ! Bne elsepart 20 ! Cmps R2,R3 21 ! Bne elsepart 22 ! Mov R0,R2 23 ! 24 ! CmpS R0,R1 RULE (C) ABOVE 25 ! Bne elsepart 26 ! CmpS R2,R3 27 ! MovEQ R0,R2 28 ! 29 ! CmpS R0,R1 RULE (D) SPECIAL CASE 30 ! CmpSEQ R2,R3 31 ! MovEQ R0,R2 32 ! 33 ! E) alters conditions to generate similar condition codes on 34 ! condition AND condition AND condition to generate more cases 35 ! to which rule (D) can be applied. 36 ! 37 ! F) adjusts constants in < or <= cases to favour above, i.e. turning 38 ! CMP R,#const & BLE ... into CMP R,#const-1 & BLT ... etc. 39 ! 40 ! G) changes Newline back from the current implicit printsymbol(10) - 41 ! there is no run-time overhead in moving the MOV R0,#10 over to 42 ! the procedure body instead of having it in every call where it 43 ! takes up space - after all, Peter's code-moving stuff ought to 44 ! get %permroutine newline;printsymbol(10);%end correct - it will 45 ! place the Mov R0,#10 before the body of %permroutine printsymbol 46 ! and generate a suitable entry point for it... 47 ! Personally, I would recommend stacking/restoring R0 as well 48 ! as it might keep another variable in a register for a bit longer... 49 ! 50 ! I've only suggested optimisations which fit into the style of PSR's 51 ! compilers... 52 ! 53 54 55 %begin 000008 00220035 00000000 |5.".....| 000010 E28CBF00 ADD R11, R12, #16_00000000 =0 000014 E92C4E20 STMDB R12!, {R5,R9,R10,R11,R14} 000018 E51F9014 LDR R9, [PC, #-16_014] 00001C E1A0A00C MOV R10, R12 000020 E24CCF03 SUB R12, R12, #16_0000000C =12 56 %integer a,i,b 57 58 read(a) 000024 EB000000 BL 16_00002C 000028 E50A0004 STR R0, [R10, #-16_004] 59 ! BL read_fn 60 61 ! Str R0,a 62 read(i) 00002C EB000000 BL 16_000034 000030 E50A0008 STR R0, [R10, #-16_008] 63 ! BL read_fn 64 65 ! Str R0,i 66 read(b) 000034 EB000000 BL 16_00003C 000038 E50A000C STR R0, [R10, #-16_00C] 67 ! BL read_fn 68 69 %if a <= i <= b %start 00003C E51A1004 LDR R1, [R10, #-16_004] 000040 E51A2008 LDR R2, [R10, #-16_008] 000044 E1510002 CMPS R1, R2 000048 CA000003 BGT 16_00005C 00004C E1520000 CMPS R2, R0 000050 CA000001 BGT 16_00005C 70 ! Ldr R1,a 71 ! Ldr R2,i 72 ! CmpS R1,R2 73 ! CmpSLE R2,R0 74 i = 22 000054 E3A02016 MOV R2, #16_00000016 =22 000058 E50A2008 STR R2, [R10, #-16_008] 75 ! MovLE R2,#22 76 %finish 77 78 %if 22 <= i <= b %start 00005C E3520016 CMPS R2, #16_00000016 =22 000060 BA000003 BLT 16_000074 000064 E1520000 CMPS R2, R0 000068 CA000001 BGT 16_000074 79 ! CmpS R2,#22-1 80 ! CmpSGT R2,R0 81 i = 44 00006C E3A02F0B MOV R2, #16_0000002C =44 ',' 000070 E50A2008 STR R2, [R10, #-16_008] 82 ! MovGT R2,#44 83 %finish 84 85 %if a <= i <= 77 %start 000074 E1510002 CMPS R1, R2 000078 CA000003 BGT 16_00008C 00007C E352004D CMPS R2, #16_0000004D =77 'M' 000080 CA000001 BGT 16_00008C 86 ! CmpS R1,R2 87 ! CmpSLE R2,#77 88 i = 99 000084 E3A02063 MOV R2, #16_00000063 =99 'c' 000088 E50A2008 STR R2, [R10, #-16_008] 89 ! MovLE R2,#99 90 %finish 91 92 %if 11 <= i <= 100 %start ;! Peter's special case when both const is good 00008C E242200B SUB R2, R2, #16_0000000B =11 000090 E3520059 CMPS R2, #16_00000059 =89 'Y' 93 ! Sub R2,#11 ;! but usually corrupts a register needed later 94 ! CmpS R2,#100-11 95 i = 1 000094 93A02001 MOVLS R2, #16_00000001 =1 000098 950A2008 STRLS R2, [R10, #-16_008] 96 ! MovLS R2,#1 97 %finish 98 99 ! Str R0,b 100 write(a,0) 00009C E1A00001 MOV R0, R1 0000A0 E3A01000 MOV R1, #16_00000000 =0 0000A4 EB000000 BL 16_0000AC 101 ! Mov R0,R1 102 ! Mov R1,#0 103 ! Bl Write 104 105 newline 0000A8 E3A0000A MOV R0, #16_0000000A =10 0000AC EB00000B BL 16_0000E0 106 ! Bl Newline 107 108 ! Mov R0,R2 109 write(i,0) 0000B0 E51A0008 LDR R0, [R10, #-16_008] 0000B4 E3A01000 MOV R1, #16_00000000 =0 0000B8 EB000000 BL 16_0000C0 110 ! Bl write 111 112 newline 0000BC E3A0000A MOV R0, #16_0000000A =10 0000C0 EB000006 BL 16_0000E0 113 ! Bl newline 114 115 write(b,0) 0000C4 E51A000C LDR R0, [R10, #-16_00C] 0000C8 E3A01000 MOV R1, #16_00000000 =0 0000CC EB000000 BL 16_0000D4 116 ! Ldr R0,b 117 ! Bl write 118 119 newline 0000D0 E3A0000A MOV R0, #16_0000000A =10 0000D4 EB000001 BL 16_0000E0 120 ! Bl newline 121 122 %endofprogram 0000D8 E8DA9620 LDMIA R10, {R5,R9,R10,R12,PC}^ 0000DC 00100000 |....| 0000E0 E5991000 LDR R1, [R9] 0000E4 E5911000 LDR R1, [R1] 0000E8 E891007C LDMIA R1, {R2,R3,R4,R5,R6} 0000EC E1500005 CMPS R0, R5 0000F0 D1A0F006 MOVLE PC, R6 0000F4 E1520003 CMPS R2, R3 0000F8 A1A0F004 MOVGE PC, R4 0000FC E4C20001 STRB R0, [R2], #16_001 000100 E4812000 STR R2, [R1] 000104 E1A0F00E MOV PC, R14 000000 EA000000 F82F0000 |....../.| Dump of Data Area 000000 00000000 |....| Finished after 2 min, 00.65 sec. *spool