+%include "macros.S"
+
extern memmove
+extern free
+extern realloc
global shiftLeft
global shiftRight
section .text
+; shrinks array (4byte) by shifting blocks left
+; args: buffer, buffer_len, shift_pos (index that gets destroyed)
+; return:
+; eax: location of new buffer
+; issues:
shiftLeft:
+ %define _BUFFER 16
+ %define _BUFFER_LEN 12
+ %define _SHIFT_POS 8
+ %define SHIFT_LEN 4
+ %define BLOCK_OFFSET 8 ; mem location of block to be destroyed
+ %define NEW_BUFFER 12
+
push ebp
mov ebp, esp
+
+ sub esp, 12
+
+ ; set vars
+ mov eax, DWORD [ebp+_BUFFER_LEN]
+ sub eax, [ebp+_SHIFT_POS]
+ sub eax, 1
+ mov [ebp-SHIFT_LEN], eax
+
+ str_offset [ebp+_BUFFER], [ebp+_SHIFT_POS]
+ mov [ebp-BLOCK_OFFSET], eax
+ ; free string to be destoryed first
+ mov eax, DWORD [ebp-BLOCK_OFFSET]
+ mov eax, [eax]
+ push eax
+ call free
+
+ ; move the memory
+ mov eax, DWORD [ebp-SHIFT_LEN]
+ mov ecx, 4
+ mul ecx
+ push eax
+ mov eax, DWORD [ebp-BLOCK_OFFSET]
+ add eax, 4
+ push eax
+ push DWORD [ebp-BLOCK_OFFSET]
+ call memmove
+ ; realloc to shrink the array
+
+ %undef _BUFFER
+ %undef _BUFFER_LEN
+ %undef _SHIFT_POS
mov esp, ebp
pop ebp
ret
+; grows array by shifting blocks right
+; args: buffer, buffer_len, shift_pos (new uninitalized index)
+; return: location of new buffer
shiftRight:
push ebp
mov ebp, esp
mov esp, ebp
pop ebp
ret
+
