1 /* -------------------------------------------------- 2 Define required labels for EGTAPI 3 -------------------------------------------------- */ 4 .global main, Stop, CodeEnd, DataStart, DataEnd 5 6 .global A 7 8 /* -------------------------------------------------- 9 Begin of the program instructions 10 -------------------------------------------------- */ 11 .text 12 main: 13 0000 6F00A0E3 mov r0, #111 // Pass 111 as parameter 1 in r0 14 0004 DE10A0E3 mov r1, #222 // Pass 222 as parameter 2 in r1 15 16 0008 030000EB bl f // Calls f(111, 222) 17 18 // When f returns, you will see the return value in r0 = 999 19 20 000c 001000E3 movw r1, #:lower16:x 21 0010 001040E3 movt r1, #:upper16:x 22 0014 000081E5 str r0, [r1] // Assigns: x = f(111,222) 23 Stop: 24 0018 0000A0E1 nop 25 26 27 /* =============================== 28 Leaf function 29 =============================== */ 30 f: 31 // When run in EGTAPI - you will see r0 = 111 and r1 = 222 32 001c 0000A0E1 nop 33 0020 0000A0E1 nop 34 0024 0000A0E1 nop 35 36 0028 E70300E3 mov r0, #999 // Return 999 in R0 37 38 002c 0EF0A0E1 mov pc, lr 39 40 41 CodeEnd: 42 0030 0000A0E1 nop 43 44 /* -------------------------------------------------- 45 Begin of the permanent program variables 46 -------------------------------------------------- */ 47 .data 48 DataStart: 49 0000 00000000 x: .skip 4 50 51 DataEnd: 52 53 .end DEFINED SYMBOLS /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:12 .text:0000000000000000 main /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:23 .text:0000000000000018 Stop /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:41 .text:0000000000000030 CodeEnd /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:48 .data:0000000000000000 DataStart /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:51 .data:0000000000000004 DataEnd /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:13 .text:0000000000000000 $a /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:30 .text:000000000000001c f /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:49 .data:0000000000000000 x /home/cs255001/cs255/asm/8-sub/skel-reg-param.s:49 .data:0000000000000000 $d UNDEFINED SYMBOLS A 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