source: xtideuniversalbios/trunk/Assembly_Library/Src/Display/CgaSnow.asm@ 592

Last change on this file since 592 was 592, checked in by Krister Nordvall, 6 years ago

Changes:

  • The problem with NASM in the previous revision (r591) has been fixed.
  • The colors used by the boot menu and hotkey bar can now be customized by selecting one of a number of pre-defined color themes. Suggestions for additional themes are more than welcome!
  • Large builds are now 10 KB. Small builds are still 8 KB with the exception of the Tiny build which is now 4 KB. In other words, builds are now as small as possible to make it easier to combine them with other BIOSes.
  • Added code to the library to improve drive error handling. XTIDECFG can now handle "Drive Not Ready" errors.
  • Fixed a couple of potential bugs in AtaID.asm (AtaID_GetMaxPioModeToAXandMinCycleTimeToCX); 1) ATA1.bPioMode was treated as a WORD variable. 2) ATA2.bPIOSupp was assumed to be non-zero which would result in PIO mode 3 being returned if the assumption was wrong.
  • Made the same changes in the equivalent function used by BIOSDRVS (DisplayPioModeInformationUsingAtaInfoFromDSBX in AtaInfo.asm).
  • Fixed a bug from r587 in PDC20x30.asm in PDC20x30_GetMaxPioModeToALandMinPioCycleTimeToBX.
  • Fixed a bug from r523 in XTIDECFG where Auto Configure would only set the IRQ on one IDE interface on AT-builds.
  • XTIDECFG will now restore the default settings for the "Serial port virtual device" when reselecting it in the list of device types. This makes it behave consistently for all device types.
  • The eAAM macro is now used regardless if USE_UNDOC_INTEL is defined or not because it is apparently supported on all processors including the NEC V20/V30 CPUs.
  • Renamed the EXCLUDE_FROM_XTIDE_UNIVERSAL_BIOS define to EXCLUDE_FROM_XUB.
  • Added a define to exclude unused library code from BIOSDRVS (EXCLUDE_FROM_BIOSDRVS). This makes it a lot smaller than in previous revisions.
  • All unnecessary CLD-instructions are now under a new define 'CLD_NEEDED' which is only enabled for the BIOS. It is disabled for XTIDECFG and BIOSDRVS but can be enabled if needed by adding this define to the respective makefile. This change was made because these unnecessary instructions are wasteful and should never be needed. In fact, they only serve to hide bugs (in other peoples code) which I strongly believe should be avoided. I recommend people making their own BIOSes from source to not use this define as it's extremely unlikely to be needed.
  • Updated the copyright info in SerDrive and changed an URL to point to the new site.
  • Updated the copyright info and version number in BIOSDRVS.
  • Updated the copyright info in XTIDECFG.
  • Optimizations in general.
File size: 4.3 KB
Line 
1; Project name : Assembly Library
2; Description : Functions for preventing CGA snow.
3
4;
5; XTIDE Universal BIOS and Associated Tools
6; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
7;
8; This program is free software; you can redistribute it and/or modify
9; it under the terms of the GNU General Public License as published by
10; the Free Software Foundation; either version 2 of the License, or
11; (at your option) any later version.
12;
13; This program is distributed in the hope that it will be useful,
14; but WITHOUT ANY WARRANTY; without even the implied warranty of
15; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16; GNU General Public License for more details.
17; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
18;
19
20; Section containing code
21SECTION .text
22
23;--------------------------------------------------------------------
24; CgaSnow_IsCgaPresent
25; Parameters:
26; DS: BDA segment (zero)
27; Returns:
28; CF: Set if CGA detected
29; Cleared if CGA not detected
30; Corrupts registers:
31; Nothing
32;--------------------------------------------------------------------
33ALIGN DISPLAY_JUMP_ALIGN
34CgaSnow_IsCgaPresent:
35 cmp WORD [BDA.wVidPort], CGA_STATUS_REGISTER - OFFSET_TO_CGA_STATUS_REGISTER
36 jne SHORT .CgaNotFound
37
38 ; All standard CGA modes use 25 rows but only EGA and later store it to BDA.
39 cmp BYTE [BDA.bVidRows], 25 ; *FIXME* Shouldn't this be 24 (rows - 1)?
40 jae SHORT .CgaNotFound
41 ret
42ALIGN DISPLAY_JUMP_ALIGN
43.CgaNotFound:
44 clc
45 ret
46
47
48; CGA snow prevention must be kept optional to avoid unnecessary
49; overhead when building programs meant for non-CGA systems.
50%ifdef ELIMINATE_CGA_SNOW
51
52;--------------------------------------------------------------------
53; CgaSnow_Stosb
54; CgaSnow_Stosw
55; Parameters:
56; AL: Character to output
57; AH: Attribute to output (CgaSnow_StoswWithoutCgaSnow only)
58; DS: BDA segment (zero)
59; ES:DI: Ptr to video memory where to output
60; Returns:
61; DI: Incremented for next character
62; Corrupts registers:
63; AX, DX
64;--------------------------------------------------------------------
65ALIGN DISPLAY_JUMP_ALIGN
66CgaSnow_Stosb:
67 call LoadCgaStatusRegisterAddressToDXifCgaPresent
68 jz SHORT .StosbWithoutWaitSinceUnknownPort
69
70 mov ah, al
71 cli ; Interrupt request would mess up timing
72 WAIT_UNTIL_SAFE_CGA_WRITE
73 mov al, ah
74.StosbWithoutWaitSinceUnknownPort:
75 stosb
76 sti
77 ret
78
79ALIGN DISPLAY_JUMP_ALIGN
80CgaSnow_Stosw:
81 push bx
82 call LoadCgaStatusRegisterAddressToDXifCgaPresent
83 jz SHORT .StoswWithoutWaitSinceUnknownPort
84
85 xchg bx, ax
86 cli ; Interrupt request would mess up timing
87 WAIT_UNTIL_SAFE_CGA_WRITE
88 xchg ax, bx
89.StoswWithoutWaitSinceUnknownPort:
90 stosw
91 sti
92 pop bx
93 ret
94
95
96;--------------------------------------------------------------------
97; CgaSnow_RepMovsb
98; Parameters:
99; CX: Number of characters to copy
100; DS: BDA segment (zero)
101; ES:SI: Ptr to video memory where to read from
102; ES:DI: Ptr to video memory where to write to
103; Returns:
104; SI, DI: Updated for next character
105; Corrupts registers:
106; AX, CX, DX
107;--------------------------------------------------------------------
108%ifdef EXCLUDE_FROM_XUB
109 %ifdef MODULE_STRINGS_COMPRESSED
110 %define EXCLUDE
111 %endif
112 %ifdef MODULE_BOOT_MENU
113 %undef EXCLUDE
114 %endif
115%endif
116
117%ifndef EXCLUDE
118ALIGN DISPLAY_JUMP_ALIGN
119CgaSnow_RepMovsb:
120 call LoadCgaStatusRegisterAddressToDXifCgaPresent
121 jz SHORT .RepMovsbWithoutWaitSinceUnknownPort
122
123.MovsbNextByte:
124 cli ; Interrupt request would mess up timing
125 WAIT_UNTIL_SAFE_CGA_WRITE
126 es movsb
127 sti
128 loop .MovsbNextByte
129 ret
130.RepMovsbWithoutWaitSinceUnknownPort:
131 eSEG_STR rep, es, movsb
132 ret
133%endif
134%undef EXCLUDE
135
136
137;--------------------------------------------------------------------
138; LoadCgaStatusRegisterAddressToDXifCgaPresent
139; Parameters:
140; DS: BDA segment (zero)
141; Returns:
142; DX: CGA Status Register Address
143; ZF: Set if CGA not present
144; Cleared if CGA present
145; Corrupts registers:
146; Nothing
147;--------------------------------------------------------------------
148ALIGN DISPLAY_JUMP_ALIGN
149LoadCgaStatusRegisterAddressToDXifCgaPresent:
150 test BYTE [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bFlags], FLG_CONTEXT_CGA
151 jz SHORT .NoCgaDetected
152 mov dx, CGA_STATUS_REGISTER
153ALIGN DISPLAY_JUMP_ALIGN, ret
154.NoCgaDetected:
155 ret
156
157
158%endif ; ELIMINATE_CGA_SNOW
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