source: xtideuniversalbios/trunk/Assembly_Library/Src/Util/Memory.asm@ 132

Last change on this file since 132 was 131, checked in by Tomi Tilli, 14 years ago

Changes to Assembly Library:

  • Some functions are now excluded from XTIDE Universal BIOS with EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS define.
File size: 3.2 KB
RevLine 
[41]1; Project name : Assembly Library
2; Description : Functions for memory access.
3
4; Section containing code
5SECTION .text
6
7;--------------------------------------------------------------------
[46]8; OPTIMIZE_STRING_OPERATION
[41]9; Parameters
[46]10; %1: Repeat instruction
11; %2: String instruction without size (for example MOVS and not MOVSB or MOVSW)
12; CX: Number of BYTEs to operate
13; DS:SI: Ptr to source data
14; ES:DI: Ptr to destination
[41]15; Returns:
[46]16; SI, DI: Updated by number of bytes operated
17; Corrupts registers:
[41]18; Nothing
[46]19;--------------------------------------------------------------------
20%macro OPTIMIZE_STRING_OPERATION 2
21 push cx
22
23 shr cx, 1 ; Operate with WORDs for performance
[103]24 jz %%HandleRemainingByte
[46]25 %1 %2w
26%%HandleRemainingByte:
27 jnc SHORT %%OperationCompleted
28 %2b
29
30ALIGN JUMP_ALIGN
31%%OperationCompleted:
32 pop cx
33%endmacro
34
35
36;--------------------------------------------------------------------
37; Memory_CopyCXbytesFromDSSItoESDI
38; Parameters
39; CX: Number of bytes to copy
40; DS:SI: Ptr to source data
41; ES:DI: Ptr to destination buffer
42; Returns:
43; SI, DI: Updated by number of bytes copied
[41]44; Corrupts registers:
[46]45; Nothing
[41]46;--------------------------------------------------------------------
[131]47%ifndef EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS
[41]48ALIGN JUMP_ALIGN
[46]49Memory_CopyCXbytesFromDSSItoESDI:
50 OPTIMIZE_STRING_OPERATION rep, movs
51 ret
[131]52%endif
[41]53
[46]54
[41]55;--------------------------------------------------------------------
[46]56; Memory_ZeroSSBPwithSizeInCX
[41]57; Parameters
[46]58; CX: Number of bytes to zero
[41]59; SS:BP: Ptr to buffer to zero
60; Returns:
61; Nothing
62; Corrupts registers:
63; Nothing
64;--------------------------------------------------------------------
65ALIGN JUMP_ALIGN
[46]66Memory_ZeroSSBPwithSizeInCX:
[50]67 push es
68 push di
[41]69 push ax
[105]70 call Registers_CopySSBPtoESDI
[46]71 call Memory_ZeroESDIwithSizeInCX
[41]72 pop ax
[50]73 pop di
74 pop es
[41]75 ret
76
77;--------------------------------------------------------------------
[46]78; Memory_ZeroESDIwithSizeInCX
[41]79; Parameters
[46]80; CX: Number of bytes to zero
81; ES:DI: Ptr to destination buffer
[41]82; Returns:
[50]83; DI: Updated by number of BYTEs stored
[41]84; Corrupts registers:
85; AX
86;--------------------------------------------------------------------
87ALIGN JUMP_ALIGN
[46]88Memory_ZeroESDIwithSizeInCX:
[41]89 xor ax, ax
[46]90 ; Fall to Memory_StoreCXbytesFromAccumToESDI
[41]91
92;--------------------------------------------------------------------
[46]93; Memory_StoreCXbytesFromAccumToESDI
[41]94; Parameters
95; AX: Word to use to fill buffer
[46]96; CX: Number of BYTEs to store
97; ES:DI: Ptr to destination buffer
[41]98; Returns:
[50]99; DI: Updated by number of BYTEs stored
[41]100; Corrupts registers:
101; Nothing
102;--------------------------------------------------------------------
103ALIGN JUMP_ALIGN
[46]104Memory_StoreCXbytesFromAccumToESDI:
105 OPTIMIZE_STRING_OPERATION rep, stos
[41]106 ret
107
108
109;--------------------------------------------------------------------
110; Memory_ReserveCXbytesFromStackToDSSI
111; Parameters
112; CX: Number of bytes to reserve
113; Returns:
114; DS:SI: Ptr to reserved buffer
115; Corrupts registers:
116; AX
117;--------------------------------------------------------------------
118ALIGN JUMP_ALIGN
119Memory_ReserveCXbytesFromStackToDSSI:
120 pop ax
121 push ss
122 pop ds
123 sub sp, cx
124 mov si, sp
125 jmp ax
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