1 /* -------------------------------------------------- 2 Show actions of both prelude and postlude 3 4 f( ): has 2 int parameters and 3 int local vars 5 g( ): has 3 int parameters and 2 int local vars 6 -------------------------------------------------- */ 7 8 .global main, Stop, CodeEnd, DataStart, DataEnd 9 10 .global f, g 11 12 /* -------------------------------------------------- 13 Begin of the program instructions 14 -------------------------------------------------- */ 15 .text 16 main: 17 0000 DE00A0E3 mov r0, #222 // Pass 222 as parameter 2 on stack 18 0004 04002DE5 push {r0} 19 0008 6F00A0E3 mov r0, #111 // Pass 111 as parameter 1 on stack 20 000c 04002DE5 push {r0} 21 22 0010 FEFFFFEB bl f // Use step-in to call function f 23 0014 08D08DE2 add sp, sp, #8 // De-allocate 2 int parameters 24 25 0018 0000A0E1 nop 26 001c 0000A0E1 nop 27 28 29 /* ============================================== 30 Function f: param and locals in stack 31 ============================================== */ 32 f: 33 /* **************************************** 34 Prelude: build stack frame 35 **************************************** */ 36 0020 04E02DE5 push {lr} // Save return address in LR 37 0024 04B02DE5 push {fp} // Save Frame Pointer in FP 38 0028 0DB0A0E1 mov fp, sp // Initialize my own FP 39 002c 0CD04DE2 sub sp, sp, #12 // I create 3 local variable in stack 40 41 /* BODY of function f */ 42 0030 0000A0E1 nop // These instructions in f( ) can use stack 43 0034 0000A0E1 nop // to access parameters and local variables 44 45 46 0038 2B0200E3 mov r0, #555 // Pass 555 as parameter 3 on stack 47 003c 04002DE5 push {r0} 48 0040 6F0FA0E3 mov r0, #444 // Pass 444 as parameter 2 on stack 49 0044 04002DE5 push {r0} 50 0048 4D0100E3 mov r0, #333 // Pass 333 as parameter 1 on stack 51 004c 04002DE5 push {r0} 52 53 0050 FEFFFFEB bl g // Use step-in to call function g 54 0054 0CD08DE2 add sp, sp, #12 // De-allocate 3 int parameters 55 56 0058 0000A0E1 nop 57 005c 0000A0E1 nop 58 59 /* **************************************** 60 Postlude: tear down stack frame 61 **************************************** */ 62 0060 0BD0A0E1 mov sp, fp 63 0064 04B09DE4 pop {fp} 64 0068 04F09DE4 pop {pc} 65 66 /* ============================================== 67 Function g: param and locals in stack 68 ============================================== */ 69 g: 70 /* **************************************** 71 Prelude: build stack frame 72 **************************************** */ 73 006c 04E02DE5 push {lr} // Save return address in LR 74 0070 04B02DE5 push {fp} // Save Frame Pointer in FP 75 0074 0DB0A0E1 mov fp, sp // Initialize my own FP 76 0078 08D04DE2 sub sp, sp, #8 // I create 2 local variable in stack 77 78 /* BODY of function g */ 79 007c 0000A0E1 nop // These instructions in f( ) can use stack 80 0080 0000A0E1 nop // to access parameters and local variables 81 82 /* **************************************** 83 Postlude: tear down stack frame 84 **************************************** */ 85 0084 0BD0A0E1 mov sp, fp 86 0088 04B09DE4 pop {fp} 87 008c 04F09DE4 pop {pc} 88 89 90 91 92 CodeEnd: 93 Stop: 94 0090 0000A0E1 nop 95 96 /* -------------------------------------------------- 97 Begin of the permanent program variables 98 -------------------------------------------------- */ 99 .data 100 DataStart: 101 102 DataEnd: 103 104 .end DEFINED SYMBOLS /home/cs255001/cs255/asm/8-sub/pre+postlude.s:16 .text:0000000000000000 main /home/cs255001/cs255/asm/8-sub/pre+postlude.s:93 .text:0000000000000090 Stop /home/cs255001/cs255/asm/8-sub/pre+postlude.s:92 .text:0000000000000090 CodeEnd /home/cs255001/cs255/asm/8-sub/pre+postlude.s:100 .data:0000000000000000 DataStart /home/cs255001/cs255/asm/8-sub/pre+postlude.s:102 .data:0000000000000000 DataEnd /home/cs255001/cs255/asm/8-sub/pre+postlude.s:32 .text:0000000000000020 f /home/cs255001/cs255/asm/8-sub/pre+postlude.s:69 .text:000000000000006c g /home/cs255001/cs255/asm/8-sub/pre+postlude.s:17 .text:0000000000000000 $a NO UNDEFINED SYMBOLS 1 2 .global malloc, print 3 .global stdout_start, stdout_end 4 5 // ********************************************** 6 // malloc: simulate memory allocate 7 // 8 // This function will NOT change ANY registers 9 // (I.e.: will preserve ALL registers) 10 // ********************************************** 11 malloc: 12 0000 0E002DE9 push {r1, r2, r3} // Save scratch registers 13 14 0004 001000E3 movw r1, #:lower16:maddr 15 0008 001040E3 movt r1, #:upper16:maddr // r1 = &maddr 16 000c 003091E5 ldr r3, [r1] // r3 = maddr 17 18 // -------------------------------------- 19 // Make new maddr (divisible by 8) 20 // -------------------------------------- 21 22 0010 002083E0 add r2, r3, r0 // New maddr 23 0014 082082E2 add r2, r2, #8 // Making sure it increase 24 25 0018 0700A0E3 mov r0, #0x7 // r0 = 0000..00111 26 001c 0000E0E1 mvn r0, r0 // r0 = 1111..11000 27 0020 002002E0 and r2, r2, r0 // Knock off the last 3 bits 28 0024 002081E5 str r2, [r1] // Update maddr 29 30 31 // -------------------------------------- 32 // Return to caller 33 // -------------------------------------- 34 0028 0300A0E1 mov r0, r3 // Return maddr value in r0 35 002c 0E00BDE8 pop {r1, r2, r3} // Restore scratch registers 36 0030 0EF0A0E1 mov pc, lr // Return 37 38 0034 00000400 maddr: .word 0x40000 // Start address of the heap 39 40 41 // ******************************************************************* 42 // print: simulate print output in Egtapi 43 // 44 // input: r0 = address of string 45 // r1 = # characters to write 46 // 47 // Egtapi will show ASCII data stored starting at stdout_start 48 // until stdout_end in its output area 49 // 50 // This function will NOT change ANY registers 51 // (I.e.: will preserve ALL registers) 52 // ******************************************************************* 53 print: 54 0038 1C002DE9 push {r2, r3, r4} // Save scratch registers 55 56 003c 002000E3 movw r2, #:lower16:stdout_end 57 0040 002040E3 movt r2, #:upper16:stdout_end // r2 = &stdout_end 58 0044 002092E5 ldr r2, [r2] // r2 = stdout_end 59 60 0048 0130A0E1 mov r3, r1 // r3 = # char to copy 61 62 printLoop: 63 004c 000053E3 cmp r3, #0 64 0050 0500000A beq printDone 65 66 0054 0040D0E5 ldrb r4, [r0] // Get next char 67 0058 0040C2E5 strb r4, [r2] // Write next char 68 69 005c 010080E2 add r0, r0, #1 70 0060 012082E2 add r2, r2, #1 71 72 0064 013043E2 sub r3, r3, #1 73 74 0068 F7FFFFEA b printLoop 75 76 printDone: 77 006c 2040A0E3 mov r4, #32 // Space 78 0070 0040C2E5 strb r4, [r2] 79 0074 012082E2 add r2, r2, #1 80 81 0078 003000E3 movw r3, #:lower16:stdout_end 82 007c 003040E3 movt r3, #:upper16:stdout_end // r2 = &stdout_end 83 0080 002083E5 str r2, [r3] 84 85 0084 1C00BDE8 pop {r2, r3, r4} // Restore scratch registers 86 0088 0EF0A0E1 mov pc, lr // Return 87 88 89 90 91 008c 00000500 stdout_start: .word 0x50000 // This value remains unchanged 92 0090 00000500 stdout_end: .word 0x50000 93 94 95 .end DEFINED SYMBOLS /home/egtapi/lib/cs255lib.s:11 .text:0000000000000000 malloc /home/egtapi/lib/cs255lib.s:53 .text:0000000000000038 print /home/egtapi/lib/cs255lib.s:91 .text:000000000000008c stdout_start /home/egtapi/lib/cs255lib.s:92 .text:0000000000000090 stdout_end /home/egtapi/lib/cs255lib.s:12 .text:0000000000000000 $a /home/egtapi/lib/cs255lib.s:38 .text:0000000000000034 maddr /home/egtapi/lib/cs255lib.s:38 .text:0000000000000034 $d /home/egtapi/lib/cs255lib.s:54 .text:0000000000000038 $a /home/egtapi/lib/cs255lib.s:62 .text:000000000000004c printLoop /home/egtapi/lib/cs255lib.s:76 .text:000000000000006c printDone /home/egtapi/lib/cs255lib.s:91 .text:000000000000008c $d NO UNDEFINED SYMBOLS