[186] | 1 | ; Project name : Assembly Library |
---|
| 2 | ; Description : Functions for displaying formatted strings. |
---|
[202] | 3 | ; ** Compressed Strings edition ** |
---|
| 4 | ; This is a plug replacement for DisplayFormat.asm, |
---|
| 5 | ; working instead with precompiled and slightly compressed strings. |
---|
[376] | 6 | |
---|
[186] | 7 | ; |
---|
[445] | 8 | ; XTIDE Universal BIOS and Associated Tools |
---|
[526] | 9 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
---|
[376] | 10 | ; |
---|
| 11 | ; This program is free software; you can redistribute it and/or modify |
---|
| 12 | ; it under the terms of the GNU General Public License as published by |
---|
| 13 | ; the Free Software Foundation; either version 2 of the License, or |
---|
| 14 | ; (at your option) any later version. |
---|
[445] | 15 | ; |
---|
[376] | 16 | ; This program is distributed in the hope that it will be useful, |
---|
| 17 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
---|
| 18 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
---|
[445] | 19 | ; GNU General Public License for more details. |
---|
[376] | 20 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
---|
| 21 | ; |
---|
| 22 | |
---|
| 23 | ;============================================================================================= |
---|
| 24 | ; |
---|
[186] | 25 | ; Strings are compressed in a simple manner: |
---|
| 26 | ; 1. The two most common characters, space and null, are removed |
---|
[202] | 27 | ; 2. Format specifiers are reduced to a single byte, including length information |
---|
[186] | 28 | ; |
---|
| 29 | ; Format of bytes in the string are: |
---|
| 30 | ; 01 xxxxxx Character in x plus StringsCompressed_NormalBase |
---|
| 31 | ; 10 xxxxxx Character in x plus StringsCompressed_NormalBase, followed by a null (last character) |
---|
[202] | 32 | ; 11 xxxxxx Character in x plus StringsCompressed_NormalBase, followed by a space |
---|
[186] | 33 | ; 00 1 yyyyy Character/Format in lookup table StringsCopmressed_TranslatesAndFormats |
---|
| 34 | ; 00 0 yyyyy Character/Format in lookup table StringsCompressed_TranslatesAndFormats, followed by a null |
---|
| 35 | ; |
---|
| 36 | ; StringsCompressed_NormalBase is defined by the compressor, but is usually around 0x40, |
---|
| 37 | ; which gives a range of 0x40 to 0x7f, or roughly the upper and lower case letters. |
---|
| 38 | ; |
---|
| 39 | ; StringsCompressed_TranslatesAndFormats is a lookup table with the first few bytes being translation |
---|
| 40 | ; characters, and the last few bytes being format jump offsets from DisplayFormatCompressed_BaseFormatOffset. |
---|
| 41 | ; The dividing line is defined by StringsCompressed_FormatsBegin |
---|
| 42 | ; |
---|
| 43 | ; The assignments of the first two bits above is not by accident. The translates/format branch is 00 |
---|
[202] | 44 | ; which is easy to test for. The '01' for "normal" (no null or space) and '001' for translates/format "normal" |
---|
[186] | 45 | ; match, allowing the translates/format codes to be shifted left by 1 and then tested with the same instructions. |
---|
| 46 | ; |
---|
[202] | 47 | ; It is always possible to say that a null character follows the current character - thus there is |
---|
[186] | 48 | ; no way (nor need) to specify a zero character. |
---|
| 49 | ; |
---|
| 50 | ; Note that this code is optimized for size, not speed. Since this code is used only during initialization |
---|
| 51 | ; and only for the user interface, small performance hits should not be noticed. It will seem odd to do so |
---|
| 52 | ; much "preload", just in case a branch is taken, but that is cheaper (in size) than adding additional branches. |
---|
| 53 | ; |
---|
[202] | 54 | |
---|
[186] | 55 | ; Section containing code |
---|
| 56 | SECTION .text |
---|
| 57 | |
---|
| 58 | ;-------------------------------------------------------------------- |
---|
| 59 | ; Format Handlers |
---|
| 60 | ; |
---|
| 61 | ; Names of format handlers are DisplayFormatCompressed_Format_* where * is |
---|
[202] | 62 | ; replaced with the format code after the '%' in the original string, |
---|
[186] | 63 | ; with '-' replaced with '_'. |
---|
| 64 | ; |
---|
| 65 | ; Parameters: |
---|
| 66 | ; DS: BDA segment (zero) |
---|
[567] | 67 | ; AX: Parameter to Format |
---|
[186] | 68 | ; ES:DI: Ptr to cursor location in video RAM |
---|
| 69 | ; Returns: |
---|
| 70 | ; DI: Updated offset to video RAM |
---|
| 71 | ; Corrupts registers: |
---|
| 72 | ; AX, BX, CX, DX, SI |
---|
| 73 | ;-------------------------------------------------------------------- |
---|
| 74 | |
---|
| 75 | ; |
---|
| 76 | ; The following routines do not need any pre or post processing and can be jumped to directly. |
---|
| 77 | ; Note that they need to be within 256 bytes of DisplayFormatCompressed_BaseFormatOffset |
---|
| 78 | ; |
---|
| 79 | %define DisplayFormatCompressed_Format_c DisplayPrint_CharacterFromAL |
---|
| 80 | %define DisplayFormatCompressed_Format_nl DisplayPrint_Newline_FormatAdjustBP |
---|
| 81 | %define DisplayFormatCompressed_Format_s DisplayFormat_ParseCharacters_FromAX |
---|
| 82 | |
---|
[194] | 83 | DisplayFormatCompressed_Format_A: |
---|
[186] | 84 | mov [VIDEO_BDA.displayContext+DISPLAY_CONTEXT.bAttribute], al |
---|
| 85 | DisplayFormatCompressed_ret: ; jump target for other routines who need a "ret" |
---|
| 86 | ret |
---|
| 87 | |
---|
[241] | 88 | DisplayFormatCompressed_Format_z: |
---|
| 89 | xor bx, bx |
---|
| 90 | xchg si, ax |
---|
[580] | 91 | jmp SHORT DisplayPrint_NullTerminatedStringFromBXSI |
---|
[241] | 92 | |
---|
[186] | 93 | DisplayFormatCompressed_Format_x: |
---|
| 94 | DisplayFormatCompressed_Format_5_x: |
---|
[580] | 95 | mov si, 16 ; hex output, change base to 16 |
---|
| 96 | mov bx, (04<<8) + 'h' ; 4 bytes, with postfix character 'h' to emit |
---|
[186] | 97 | ; (note that the count includes the 'h') |
---|
[580] | 98 | SKIP2B f ; Fall through to DisplayFormatCompressed_Format_u |
---|
[186] | 99 | |
---|
| 100 | DisplayFormatCompressed_Format_2_u: |
---|
[580] | 101 | mov bh, 2 ; only two characters (instead of the default 5) |
---|
[194] | 102 | ; fall through |
---|
[202] | 103 | |
---|
[186] | 104 | DisplayFormatCompressed_Format_u: |
---|
| 105 | DisplayFormatCompressed_Format_5_u: |
---|
| 106 | push bx ; push postfix character - either a zero (default) or a 'h' |
---|
[580] | 107 | mov bl, bh ; preserve character count for .PrintLoop |
---|
[186] | 108 | |
---|
| 109 | .DivLoop: |
---|
| 110 | xor dx, dx ; Zero DX for division |
---|
| 111 | div si ; DX:AX / 10 => AX=quot, DX=rem |
---|
| 112 | push dx ; Push digit |
---|
[202] | 113 | |
---|
| 114 | dec bh |
---|
[580] | 115 | jnz SHORT .DivLoop |
---|
[186] | 116 | |
---|
| 117 | .PrintLoop: |
---|
| 118 | pop ax ; Pop digit, postfix character on last iteration |
---|
| 119 | |
---|
| 120 | dec bl ; on second to last iteration, emit digit whether it is zero or not |
---|
[580] | 121 | jz SHORT .PrintDigit |
---|
| 122 | js SHORT DisplayPrint_CharacterFromAL ; on last iteration, emit postfix character |
---|
[186] | 123 | ; if it is zero, DisplayPrint_CharacterFromAL will not emit |
---|
| 124 | |
---|
[202] | 125 | or bh, al ; skip leading zeros, bh keeps track if we have emitted anything non-zero |
---|
[580] | 126 | jnz SHORT .PrintDigit ; note that bh starts at zero, from the loop above |
---|
[186] | 127 | |
---|
[580] | 128 | test ch, 2 ; are we padding with leading spaces? |
---|
| 129 | jnz SHORT .PrintLoop ; test the even/odd of the format byte in the string |
---|
[186] | 130 | |
---|
[202] | 131 | mov al, 89h ; emit space |
---|
[186] | 132 | |
---|
[202] | 133 | .PrintDigit: |
---|
[505] | 134 | cmp al, 10 ; Convert binary digit in AL to ASCII hex digit ('0'-'9' or 'A'-'F') |
---|
| 135 | sbb al, 69h |
---|
| 136 | das |
---|
[186] | 137 | |
---|
| 138 | call DisplayPrint_CharacterFromAL |
---|
[580] | 139 | jmp SHORT .PrintLoop |
---|
[186] | 140 | |
---|
[580] | 141 | DisplayFormatCompressed_Format_2_I: |
---|
| 142 | test ax, ax |
---|
| 143 | jnz SHORT DisplayFormatCompressed_Format_2_u |
---|
| 144 | mov si, g_szDashForZero ; if parameter equals zero, emit dash string instead |
---|
| 145 | SKIP2B bx ; Fall through to DisplayFormat_ParseCharacters |
---|
[186] | 146 | |
---|
| 147 | ;-------------------------------------------------------------------- |
---|
| 148 | ; DisplayFormat_ParseCharacters |
---|
| 149 | ; Parameters: |
---|
| 150 | ; DS: BDA segment (zero) |
---|
| 151 | ; SS:BP: Pointer to first format parameter (-=2 updates to next parameter) |
---|
| 152 | ; CS:SI: Pointer to string to format |
---|
| 153 | ; ES:DI: Ptr to cursor location in video RAM |
---|
| 154 | ; Returns: |
---|
| 155 | ; CS:SI: Ptr to end of format string (ptr to one past NULL) |
---|
| 156 | ; DI: Updated offset to video RAM |
---|
| 157 | ; Corrupts registers: |
---|
| 158 | ; AX, BX, CX, DX, BP |
---|
[202] | 159 | ;-------------------------------------------------------------------- |
---|
[194] | 160 | DisplayFormatCompressed_BaseFormatOffset: |
---|
| 161 | DisplayFormat_ParseCharacters_FromAX: |
---|
[580] | 162 | mov si, ax |
---|
[194] | 163 | ; fall through to DisplayFormat_ParseCharacters |
---|
[186] | 164 | |
---|
[369] | 165 | ALIGN DISPLAY_JUMP_ALIGN |
---|
[202] | 166 | DisplayFormat_ParseCharacters: |
---|
[186] | 167 | ; |
---|
[202] | 168 | ; This routine is used to output all strings from the ROM. The strings in ROMVARS are not compressed, |
---|
[186] | 169 | ; and must be handled differently. |
---|
| 170 | ; |
---|
[580] | 171 | cmp si, BYTE 7Fh ; well within the boundaries of ROMVARS_size |
---|
| 172 | mov bx, cs ; preload bx with cs in case we take the following jump |
---|
| 173 | jb SHORT DisplayPrint_NullTerminatedStringFromBXSI |
---|
[186] | 174 | |
---|
| 175 | .decode: |
---|
[223] | 176 | cs lodsb ; load next byte of the string |
---|
[580] | 177 | mov ch, al ; save a copy for later processing of high order bits |
---|
| 178 | test al, 0C0h ; check for translation/format character |
---|
| 179 | jz SHORT DisplayFormatCompressed_TranslatesAndFormats |
---|
[186] | 180 | |
---|
[580] | 181 | and al, 3Fh ; "Normal" character, mask off high order bits |
---|
| 182 | add al, StringsCompressed_NormalBase ; and add character offset (usually around 0x40) |
---|
[186] | 183 | |
---|
| 184 | .output: |
---|
[202] | 185 | call DisplayPrint_CharacterFromAL |
---|
[186] | 186 | |
---|
| 187 | .process_after_output: |
---|
[580] | 188 | eSHL_IM ch, 1 ; check high order bits for end of string or space |
---|
| 189 | jns SHORT DisplayFormatCompressed_ret |
---|
| 190 | jnc SHORT .decode |
---|
| 191 | mov al, ' ' |
---|
[186] | 192 | call DisplayPrint_CharacterFromAL |
---|
[580] | 193 | jmp SHORT .decode |
---|
[186] | 194 | |
---|
| 195 | |
---|
[369] | 196 | ALIGN DISPLAY_JUMP_ALIGN |
---|
[202] | 197 | DisplayFormatCompressed_TranslatesAndFormats: |
---|
[186] | 198 | ; |
---|
| 199 | ; This routine is here (above DisplayFormat_ParseCharacters) to reduce the amount of code between |
---|
| 200 | ; DisplayFormatCompressed_BaseFormatOffset and jump targets (must fit in 256 bytes) |
---|
| 201 | ; |
---|
[580] | 202 | eSHL_IM ch, 1 ; setup ch for later testing of null in .process_after_output |
---|
| 203 | and ax, 001Fh ; also clears AH for addition with BX and DX below |
---|
[186] | 204 | |
---|
[580] | 205 | mov bx, StringsCompressed_TranslatesAndFormats ; calculate offset of translation/formats offset byte |
---|
| 206 | add bx, ax |
---|
[186] | 207 | |
---|
[580] | 208 | cmp al, StringsCompressed_FormatsBegin ; determine if this is a translation or a format |
---|
| 209 | mov al, [cs:bx] ; fetch translation/formats byte |
---|
| 210 | jb SHORT DisplayFormat_ParseCharacters.output ; check if this a translation or a format |
---|
[186] | 211 | ; if it is translation, output and postprocess for eos |
---|
| 212 | ; note that the flags for this conditional jump were |
---|
| 213 | ; set with the cmp al,StringsCompressed_FormatsBegin |
---|
[202] | 214 | |
---|
[580] | 215 | mov dx, DisplayFormatCompressed_BaseFormatOffset ; calculate address to jump to for format handler |
---|
| 216 | sub dx, ax |
---|
[186] | 217 | |
---|
[580] | 218 | mov ax, [bp] ; preload ax with parameter |
---|
[186] | 219 | dec bp ; if no parameter is needed (format 'nl' for example), |
---|
| 220 | dec bp ; the format handler can reincrement bp |
---|
| 221 | |
---|
[580] | 222 | mov bx, 0500h ; preload bh with 5 decimal places for numeric output |
---|
[186] | 223 | ; bl is zero, indicating not to output a 'h' (default base 10) |
---|
| 224 | |
---|
| 225 | push si ; preserve si and cx, in the case of outputing a string |
---|
| 226 | push cx |
---|
| 227 | |
---|
[580] | 228 | mov si, 10 ; preload si with 10 for numeric output (default base 10) |
---|
[186] | 229 | call dx ; call the format routine |
---|
| 230 | |
---|
| 231 | pop cx ; restore cx and si |
---|
| 232 | pop si |
---|
| 233 | |
---|
[580] | 234 | jmp SHORT DisplayFormat_ParseCharacters.process_after_output ; continue postprocessing, check for end of string |
---|