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Val 2022-09-02 06:22:36 -05:00
parent 33cfec8893
commit 89a40c6884
1 changed files with 27 additions and 8 deletions
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35
17-Chernobyl/mc-disasm.asm
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@ -288,9 +288,9 @@
4678 <malloc>
4678: 0b12 push r11
467a: c293 0424 tst.b &0x2404
467e: 0f24 jz $+0x20 <malloc+0x26>
4680: 1e42 0024 mov &0x2400, r14
467a: c293 0424 tst.b &0x2404 ; if initialized:
467e: 0f24 jz $+0x20 <malloc+0x26> ; skip, else
4680: 1e42 0024 mov &0x2400, r14 ; initialize
4684: 8e4e 0000 mov r14, 0x0(r14)
4688: 8e4e 0200 mov r14, 0x2(r14)
468c: 1d42 0224 mov &0x2402, r13
@ -301,22 +301,26 @@
; malloc+0x26:
469e: 1b42 0024 mov &0x2400, r11
46a2: 0e4b mov r11, r14
; malloc+0x2c
46a4: 1d4e 0400 mov 0x4(r14), r13
46a8: 1db3 bit #0x1, r13
46aa: 2820 jnz $+0x52 <malloc+0x84>
; This is all initialization
46a8: 1db3 bit #0x1, r13 ; if not-empty
46aa: 2820 jnz $+0x52 <malloc+0x84> ; skip, else
; check whether there's enough space in this freeblock to satisfy rq
46ac: 0c4d mov r13, r12
46ae: 12c3 clrc
46b0: 0c10 rrc r12
46b2: 0c9f cmp r15, r12
46b4: 2338 jl $+0x48 <malloc+0x84>
; Ensure the requested size plus header size is lt available space
46b6: 0b4f mov r15, r11
46b8: 3b50 0600 add #0x6, r11
46bc: 0c9b cmp r11, r12
46be: 042c jc $+0xa <malloc+0x50>
; Success! Allocate the memory
46c0: 1dd3 bis #0x1, r13
46c2: 8e4d 0400 mov r13, 0x4(r14)
46c6: 163c jmp $+0x2e <malloc+0x7c>
; malloc+0x50
46c8: 0d4f mov r15, r13
46ca: 0d5d add r13, r13
46cc: 1dd3 bis #0x1, r13
@ -331,15 +335,20 @@
46ea: 0c5c add r12, r12
46ec: 8d4c 0400 mov r12, 0x4(r13)
46f0: 8e4d 0200 mov r13, 0x2(r14)
; malloc+0x7c
; Return the address of the new block
46f4: 0f4e mov r14, r15
46f6: 3f50 0600 add #0x6, r15
46fa: 0e3c jmp $+0x1e <malloc+0xa0>
46fa: 0e3c jmp $+0x1e <malloc+0xa0> ; goto pop r11, ret
; malloc+0x84
; ensure r14->next - r14 is positive
46fc: 0d4e mov r14, r13
46fe: 1e4e 0200 mov 0x2(r14), r14
4702: 0e9d cmp r13, r14
4704: 0228 jnc $+0x6 <malloc+0x92>
; if r14 - 5000 == 0
4706: 0e9b cmp r11, r14
4708: cd23 jnz $-0x64 <malloc+0x2c>
4708: cd23 jnz $-0x64 <malloc+0x2c> ; try next block
; puts("Heap exhausted. Aborting")
470a: 3f40 5e46 mov #0x465e, r15
470e: b012 504d call #0x4d50 <puts>
@ -350,17 +359,27 @@
471c <free>
471c: 0b12 push r11
; Turn datablock pointer into metadata pointer
471e: 3f50 faff add #0xfffa, r15
; move this->size into r15
4722: 1d4f 0400 mov 0x4(r15), r13
; clear the usedbit
4726: 3df0 feff and #0xfffe, r13
; move the result into this->size
472a: 8f4d 0400 mov r13, 0x4(r15)
; move this->prev into r14
472e: 2e4f mov @r15, r14
; move this->prev->size into r12
4730: 1c4e 0400 mov 0x4(r14), r12
; if this->prev->size & 1
4734: 1cb3 bit #0x1, r12
; ... != 0, skip down
4736: 0d20 jnz $+0x1c <free+0x36>
; update prev->size
4738: 3c50 0600 add #0x6, r12
473c: 0c5d add r13, r12
473e: 8e4c 0400 mov r12, 0x4(r14)
; update prev->next
4742: 9e4f 0200 0200 mov 0x2(r15), 0x2(r14)
4748: 1d4f 0200 mov 0x2(r15), r13
474c: 8d4e 0000 mov r14, 0x0(r13)