WebSVN – SvarDOS – Diff – /svarcom/trunk/helpers.c


/*
 * a variety of helper functions
 * Copyright (C) 2021 Mateusz Viste
 */
 
#include <i86.h>    /* MK_FP() */
 
#include "helpers.h"
 
/* case-insensitive comparison of strings, returns non-zero on equality */
int imatch(const char *s1, const char *s2) {
  for (;;) {
    char c1, c2;
    c1 = *s1;
    c2 = *s2;
    if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');
    if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');
    /* */
    if (c1 != c2) return(0);
    if (c1 == 0) return(1);
    s1++;
    s2++;
  }
}
 
 
/* returns zero if s1 starts with s2 */
int strstartswith(const char *s1, const char *s2) {
  while (*s2 != 0) {
    if (*s1 != *s2) return(-1);
    s1++;
    s2++;
  }
  return(0);
}
 
 
/* outputs a NULL-terminated string to stdout */
void output_internal(const char *s, unsigned short nl) {
  _asm {
    mov ah, 0x02 /* AH=9 - write character in DL to stdout */
    mov si, s
    cld          /* clear DF so lodsb increments SI */
    NEXTBYTE:
    lodsb /* load byte from DS:SI into AL, SI++ */
    mov dl, al
    or al, 0  /* is al == 0? */
    jz DONE
    int 0x21
    jmp NEXTBYTE
    DONE:
    or nl, 0
    jz FINITO
    /* print out a CR/LF trailer if nl set */
    mov dl, 0x0D /* CR */
    int 0x21
    mov dl, 0x0A /* LF */
    int 0x21
    FINITO:
  }
}
 
 
/* find first matching files using a FindFirst DOS call
 * returns 0 on success or a DOS err code on failure */
unsigned short findfirst(struct DTA *dta, const char *pattern, unsigned short attr) {
  unsigned short res = 0;
  _asm {
    /* set DTA location */
    mov ah, 0x1a
    mov dx, dta
    int 0x21
    /* */
    mov ah, 0x4e    /* FindFirst */
    mov dx, pattern
    mov cx, attr
    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
    jnc DONE
    mov [res], ax
    DONE:
  }
  return(res);
}
 
 
/* find next matching, ie. continues an action intiated by findfirst() */
unsigned short findnext(struct DTA *dta) {
  unsigned short res = 0;
  _asm {
    mov ah, 0x4f    /* FindNext */
    mov dx, dta
    int 0x21        /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */
    jnc DONE
    mov [res], ax
    DONE:
  }
  return(res);
}
 
 
/* print s string and wait for a single key press from stdin. accepts only
 * key presses defined in the c ASCIIZ string. returns offset of pressed key
 * in string. keys in c MUST BE UPPERCASE! */
unsigned short askchoice(const char *s, const char *c) {
  unsigned short res;
  char key = 0;
 
  AGAIN:
  output(s);
  output(" ");
 
  _asm {
    push ax
    push dx
 
    mov ax, 0x0c01 /* clear input buffer and execute getchar (INT 21h,AH=1) */
    int 0x21
    /* if AL == 0 then this is an extended character */
    test al, al
    jnz GOTCHAR
    mov ah, 0x08   /* read again to flush extended char from input buffer */
    int 0x21
    xor al, al     /* all extended chars are ignored */
    GOTCHAR:       /* received key is in AL now */
    mov [key], al  /* save key */
 
    /* print a cr/lf */
    mov ah, 0x02
    mov dl, 0x0D
    int 0x21
    mov dl, 0x0A
    int 0x21
 
    pop dx
    pop ax
  }
 
  /* ucase() result */
  if ((key >= 'a') && (key <= 'z')) key -= ('a' - 'A');
 
  /* is there a match? */
  for (res = 0; c[res] != 0; res++) if (c[res] == key) return(res);
 
  goto AGAIN;
}
 
 
/* converts a path to its canonic representation, returns 0 on success
 * or DOS err on failure (invalid drive) */
unsigned short file_truename(const char *src, char *dst) {
  unsigned short res = 0;
  _asm {
    push es
    mov ah, 0x60  /* query truename, DS:SI=src, ES:DI=dst */
    push ds
    pop es
    mov si, src
    mov di, dst
    int 0x21
    jnc DONE
    mov [res], ax
    DONE:
    pop es
  }
  return(res);
}
 
 
/* returns DOS attributes of file, or -1 on error */
int file_getattr(const char *fname) {
  int res = -1;
  _asm {
    mov ax, 0x4300  /* query file attributes, fname at DS:DX */
    mov dx, fname
    int 0x21        /* CX=attributes if CF=0, otherwise AX=errno */
    jc DONE
    mov [res], cx
    DONE:
  }
  return(res);
}
 
 
/* returns screen's width (in columns) */
unsigned short screen_getwidth(void) {
  /* BIOS 0040:004A = word containing screen width in text columns */
  unsigned short far *scrw = MK_FP(0x40, 0x4a);
  return(*scrw);
}
 
 
/* returns screen's height (in rows) */
unsigned short screen_getheight(void) {
  /* BIOS 0040:0084 = byte containing maximum valid row value (EGA ONLY) */
  unsigned char far *scrh = MK_FP(0x40, 0x84);
  if (*scrh == 0) return(25);  /* pre-EGA adapter */
  return(*scrh + 1);
}
 
 
/* displays the "Press any key to continue" msg and waits for a keypress */
void press_any_key(void) {
  output("Press any key to continue...");
  _asm {
    mov ah, 0x08  /* no echo console input */
    int 0x21      /* pressed key in AL now (0 for extended keys) */
    test al, al
    jnz DONE
    int 0x21      /* executed ah=8 again to read the rest of extended key */
    DONE:
    /* output CR/LF */
    mov ah, 0x02
    mov dl, 0x0D
    int 0x21
    mov dl, 0x0A
    int 0x21
  }
}
 
 
/* validate a drive (A=0, B=1, etc). returns 1 if valid, 0 otherwise */
int isdrivevalid(unsigned char drv) {
  _asm {
    mov ah, 0x19  /* query default (current) disk */
    int 0x21      /* drive in AL (0=A, 1=B, etc) */
    mov ch, al    /* save current drive to ch */
    /* try setting up the drive as current */
    mov ah, 0x0E   /* select default drive */
    mov dl, [drv]  /* 0=A, 1=B, etc */
    int 0x21
    /* this call does not set CF on error, I must check cur drive to look for success */
    mov ah, 0x19  /* query default (current) disk */
    int 0x21      /* drive in AL (0=A, 1=B, etc) */
    mov [drv], 1  /* preset result as success */
    cmp al, dl    /* is eq? */
    je DONE
    mov [drv], 0  /* fail */
    jmp FAILED
    DONE:
    /* set current drive back to what it was initially */
    mov ah, 0x0E
    mov dl, ch
    int 0x21
    FAILED:
  }
  return(drv);
}
 

Rev 397	Rev 399
1	`/*`	1	`/*`
2	`* a variety of helper functions`	2	`* a variety of helper functions`
3	`* Copyright (C) 2021 Mateusz Viste`	3	`* Copyright (C) 2021 Mateusz Viste`
4	`*/`	4	`*/`
5		5
6	`#include <i86.h> /* MK_FP() */`	6	`#include <i86.h> /* MK_FP() */`
7		7
8	`#include "helpers.h"`	8	`#include "helpers.h"`
9		9
10	`/* case-insensitive comparison of strings, returns non-zero on equality */`	10	`/* case-insensitive comparison of strings, returns non-zero on equality */`
11	`int imatch(const char s1, const char s2) {`	11	`int imatch(const char s1, const char s2) {`
12	`for (;;) {`	12	`for (;;) {`
13	`char c1, c2;`	13	`char c1, c2;`
14	`c1 = *s1;`	14	`c1 = *s1;`
15	`c2 = *s2;`	15	`c2 = *s2;`
16	`if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');`	16	`if ((c1 >= 'a') && (c1 <= 'z')) c1 -= ('a' - 'A');`
17	`if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');`	17	`if ((c2 >= 'a') && (c2 <= 'z')) c2 -= ('a' - 'A');`
18	`/* */`	18	`/* */`
19	`if (c1 != c2) return(0);`	19	`if (c1 != c2) return(0);`
20	`if (c1 == 0) return(1);`	20	`if (c1 == 0) return(1);`
21	`s1++;`	21	`s1++;`
22	`s2++;`	22	`s2++;`
23	`}`	23	`}`
24	`}`	24	`}`
25		25
26		26
27	`/* returns zero if s1 starts with s2 */`	27	`/* returns zero if s1 starts with s2 */`
28	`int strstartswith(const char s1, const char s2) {`	28	`int strstartswith(const char s1, const char s2) {`
29	`while (*s2 != 0) {`	29	`while (*s2 != 0) {`
30	`if (s1 != s2) return(-1);`	30	`if (s1 != s2) return(-1);`
31	`s1++;`	31	`s1++;`
32	`s2++;`	32	`s2++;`
33	`}`	33	`}`
34	`return(0);`	34	`return(0);`
35	`}`	35	`}`
36		36
37		37
38	`/* outputs a NULL-terminated string to stdout */`	38	`/* outputs a NULL-terminated string to stdout */`
39	`void output_internal(const char *s, unsigned short nl) {`	39	`void output_internal(const char *s, unsigned short nl) {`
40	`_asm {`	40	`_asm {`
41	`mov ah, 0x02 /* AH=9 - write character in DL to stdout */`	41	`mov ah, 0x02 /* AH=9 - write character in DL to stdout */`
42	`mov si, s`	42	`mov si, s`
43	`cld /* clear DF so lodsb increments SI */`	43	`cld /* clear DF so lodsb increments SI */`
44	`NEXTBYTE:`	44	`NEXTBYTE:`
45	`lodsb /* load byte from DS:SI into AL, SI++ */`	45	`lodsb /* load byte from DS:SI into AL, SI++ */`
46	`mov dl, al`	46	`mov dl, al`
47	`or al, 0 /* is al == 0? */`	47	`or al, 0 /* is al == 0? */`
48	`jz DONE`	48	`jz DONE`
49	`int 0x21`	49	`int 0x21`
50	`jmp NEXTBYTE`	50	`jmp NEXTBYTE`
51	`DONE:`	51	`DONE:`
52	`or nl, 0`	52	`or nl, 0`
53	`jz FINITO`	53	`jz FINITO`
54	`/* print out a CR/LF trailer if nl set */`	54	`/* print out a CR/LF trailer if nl set */`
55	`mov dl, 0x0D /* CR */`	55	`mov dl, 0x0D /* CR */`
56	`int 0x21`	56	`int 0x21`
57	`mov dl, 0x0A /* LF */`	57	`mov dl, 0x0A /* LF */`
58	`int 0x21`	58	`int 0x21`
59	`FINITO:`	59	`FINITO:`
60	`}`	60	`}`
61	`}`	61	`}`
62		62
63		63
64	`/* find first matching files using a FindFirst DOS call`	64	`/* find first matching files using a FindFirst DOS call`
65	`* returns 0 on success or a DOS err code on failure */`	65	`* returns 0 on success or a DOS err code on failure */`
66	`unsigned short findfirst(struct DTA dta, const char pattern, unsigned short attr) {`	66	`unsigned short findfirst(struct DTA dta, const char pattern, unsigned short attr) {`
67	`unsigned short res = 0;`	67	`unsigned short res = 0;`
68	`_asm {`	68	`_asm {`
69	`/* set DTA location */`	69	`/* set DTA location */`
70	`mov ah, 0x1a`	70	`mov ah, 0x1a`
71	`mov dx, dta`	71	`mov dx, dta`
72	`int 0x21`	72	`int 0x21`
73	`/* */`	73	`/* */`
74	`mov ah, 0x4e /* FindFirst */`	74	`mov ah, 0x4e /* FindFirst */`
75	`mov dx, pattern`	75	`mov dx, pattern`
76	`mov cx, attr`	76	`mov cx, attr`
77	`int 0x21 /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */`	77	`int 0x21 /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */`
78	`jnc DONE`	78	`jnc DONE`
79	`mov [res], ax`	79	`mov [res], ax`
80	`DONE:`	80	`DONE:`
81	`}`	81	`}`
82	`return(res);`	82	`return(res);`
83	`}`	83	`}`
84		84
85		85
86	`/* find next matching, ie. continues an action intiated by findfirst() */`	86	`/* find next matching, ie. continues an action intiated by findfirst() */`
87	`unsigned short findnext(struct DTA *dta) {`	87	`unsigned short findnext(struct DTA *dta) {`
88	`unsigned short res = 0;`	88	`unsigned short res = 0;`
89	`_asm {`	89	`_asm {`
90	`mov ah, 0x4f /* FindNext */`	90	`mov ah, 0x4f /* FindNext */`
91	`mov dx, dta`	91	`mov dx, dta`
92	`int 0x21 /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */`	92	`int 0x21 /* CF set on error + err code in AX, DTA filled with FileInfoRec on success */`
93	`jnc DONE`	93	`jnc DONE`
94	`mov [res], ax`	94	`mov [res], ax`
95	`DONE:`	95	`DONE:`
96	`}`	96	`}`
97	`return(res);`	97	`return(res);`
98	`}`	98	`}`
99		99
100		100
101	`/* print s string and wait for a single key press from stdin. accepts only`	101	`/* print s string and wait for a single key press from stdin. accepts only`
102	`* key presses defined in the c ASCIIZ string. returns offset of pressed key`	102	`* key presses defined in the c ASCIIZ string. returns offset of pressed key`
103	`* in string. keys in c MUST BE UPPERCASE! */`	103	`* in string. keys in c MUST BE UPPERCASE! */`
104	`unsigned short askchoice(const char s, const char c) {`	104	`unsigned short askchoice(const char s, const char c) {`
105	`unsigned short res;`	105	`unsigned short res;`
106	`char key = 0;`	106	`char key = 0;`
107		107
108	`AGAIN:`	108	`AGAIN:`
109	`output(s);`	109	`output(s);`
110	`output(" ");`	110	`output(" ");`
111		111
112	`_asm {`	112	`_asm {`
113	`push ax`	113	`push ax`
114	`push dx`	114	`push dx`
115		115
116	`mov ax, 0x0c01 /* clear input buffer and execute getchar (INT 21h,AH=1) */`	116	`mov ax, 0x0c01 /* clear input buffer and execute getchar (INT 21h,AH=1) */`
117	`int 0x21`	117	`int 0x21`
118	`/* if AL == 0 then this is an extended character */`	118	`/* if AL == 0 then this is an extended character */`
119	`test al, al`	119	`test al, al`
120	`jnz GOTCHAR`	120	`jnz GOTCHAR`
121	`mov ah, 0x08 /* read again to flush extended char from input buffer */`	121	`mov ah, 0x08 /* read again to flush extended char from input buffer */`
122	`int 0x21`	122	`int 0x21`
123	`xor al, al /* all extended chars are ignored */`	123	`xor al, al /* all extended chars are ignored */`
124	`GOTCHAR: /* received key is in AL now */`	124	`GOTCHAR: /* received key is in AL now */`
125	`mov [key], al /* save key */`	125	`mov [key], al /* save key */`
126		126
127	`/* print a cr/lf */`	127	`/* print a cr/lf */`
128	`mov ah, 0x02`	128	`mov ah, 0x02`
129	`mov dl, 0x0D`	129	`mov dl, 0x0D`
130	`int 0x21`	130	`int 0x21`
131	`mov dl, 0x0A`	131	`mov dl, 0x0A`
132	`int 0x21`	132	`int 0x21`
133		133
134	`pop dx`	134	`pop dx`
135	`pop ax`	135	`pop ax`
136	`}`	136	`}`
137		137
138	`/* ucase() result */`	138	`/* ucase() result */`
139	`if ((key >= 'a') && (key <= 'z')) key -= ('a' - 'A');`	139	`if ((key >= 'a') && (key <= 'z')) key -= ('a' - 'A');`
140		140
141	`/* is there a match? */`	141	`/* is there a match? */`
142	`for (res = 0; c[res] != 0; res++) if (c[res] == key) return(res);`	142	`for (res = 0; c[res] != 0; res++) if (c[res] == key) return(res);`
143		143
144	`goto AGAIN;`	144	`goto AGAIN;`
145	`}`	145	`}`
146		146
147		147
148	`/* converts a path to its canonic representation */`	148	`/* converts a path to its canonic representation, returns 0 on success`
-		149	`* or DOS err on failure (invalid drive) */`
149	`void file_truename(const char src, char dst) {`	150	`unsigned short file_truename(const char src, char dst) {`
-		151	`unsigned short res = 0;`
150	`_asm {`	152	`_asm {`
-		153	`push es`
151	`mov ah, 0x60 /* query truename, DS:SI=src, ES:DI=dst */`	154	`mov ah, 0x60 /* query truename, DS:SI=src, ES:DI=dst */`
152	`push ds`	155	`push ds`
153	`pop es`	156	`pop es`
154	`mov si, src`	157	`mov si, src`
155	`mov di, dst`	158	`mov di, dst`
156	`int 0x21`	159	`int 0x21`
-		160	`jnc DONE`
-		161	`mov [res], ax`
-		162	`DONE:`
-		163	`pop es`
157	`}`	164	`}`
-		165	`return(res);`
158	`}`	166	`}`
159		167
160		168
161	`/* returns DOS attributes of file, or -1 on error */`	169	`/* returns DOS attributes of file, or -1 on error */`
162	`int file_getattr(const char *fname) {`	170	`int file_getattr(const char *fname) {`
163	`int res = -1;`	171	`int res = -1;`
164	`_asm {`	172	`_asm {`
165	`mov ax, 0x4300 /* query file attributes, fname at DS:DX */`	173	`mov ax, 0x4300 /* query file attributes, fname at DS:DX */`
166	`mov dx, fname`	174	`mov dx, fname`
167	`int 0x21 /* CX=attributes if CF=0, otherwise AX=errno */`	175	`int 0x21 /* CX=attributes if CF=0, otherwise AX=errno */`
168	`jc DONE`	176	`jc DONE`
169	`mov [res], cx`	177	`mov [res], cx`
170	`DONE:`	178	`DONE:`
171	`}`	179	`}`
172	`return(res);`	180	`return(res);`
173	`}`	181	`}`
174		182
175		183
176	`/* returns screen's width (in columns) */`	184	`/* returns screen's width (in columns) */`
177	`unsigned short screen_getwidth(void) {`	185	`unsigned short screen_getwidth(void) {`
178	`/* BIOS 0040:004A = word containing screen width in text columns */`	186	`/* BIOS 0040:004A = word containing screen width in text columns */`
179	`unsigned short far *scrw = MK_FP(0x40, 0x4a);`	187	`unsigned short far *scrw = MK_FP(0x40, 0x4a);`
180	`return(*scrw);`	188	`return(*scrw);`
181	`}`	189	`}`
182		190
183		191
184	`/* returns screen's height (in rows) */`	192	`/* returns screen's height (in rows) */`
185	`unsigned short screen_getheight(void) {`	193	`unsigned short screen_getheight(void) {`
186	`/* BIOS 0040:0084 = byte containing maximum valid row value (EGA ONLY) */`	194	`/* BIOS 0040:0084 = byte containing maximum valid row value (EGA ONLY) */`
187	`unsigned char far *scrh = MK_FP(0x40, 0x84);`	195	`unsigned char far *scrh = MK_FP(0x40, 0x84);`
188	`if (scrh == 0) return(25); / pre-EGA adapter */`	196	`if (scrh == 0) return(25); / pre-EGA adapter */`
189	`return(*scrh + 1);`	197	`return(*scrh + 1);`
190	`}`	198	`}`
191		199
192		200
193	`/* displays the "Press any key to continue" msg and waits for a keypress */`	201	`/* displays the "Press any key to continue" msg and waits for a keypress */`
194	`void press_any_key(void) {`	202	`void press_any_key(void) {`
195	`output("Press any key to continue...");`	203	`output("Press any key to continue...");`
196	`_asm {`	204	`_asm {`
197	`mov ah, 0x08 /* no echo console input */`	205	`mov ah, 0x08 /* no echo console input */`
198	`int 0x21 /* pressed key in AL now (0 for extended keys) */`	206	`int 0x21 /* pressed key in AL now (0 for extended keys) */`
199	`test al, al`	207	`test al, al`
200	`jnz DONE`	208	`jnz DONE`
201	`int 0x21 /* executed ah=8 again to read the rest of extended key */`	209	`int 0x21 /* executed ah=8 again to read the rest of extended key */`
202	`DONE:`	210	`DONE:`
203	`/* output CR/LF */`	211	`/* output CR/LF */`
204	`mov ah, 0x02`	212	`mov ah, 0x02`
205	`mov dl, 0x0D`	213	`mov dl, 0x0D`
206	`int 0x21`	214	`int 0x21`
207	`mov dl, 0x0A`	215	`mov dl, 0x0A`
208	`int 0x21`	216	`int 0x21`
209	`}`	217	`}`
210	`}`	218	`}`
-		219
-		220
-		221	`/* validate a drive (A=0, B=1, etc). returns 1 if valid, 0 otherwise */`
-		222	`int isdrivevalid(unsigned char drv) {`
-		223	`_asm {`
-		224	`mov ah, 0x19 /* query default (current) disk */`
-		225	`int 0x21 /* drive in AL (0=A, 1=B, etc) */`
-		226	`mov ch, al /* save current drive to ch */`
-		227	`/* try setting up the drive as current */`
-		228	`mov ah, 0x0E /* select default drive */`
-		229	`mov dl, [drv] /* 0=A, 1=B, etc */`
-		230	`int 0x21`
-		231	`/* this call does not set CF on error, I must check cur drive to look for success */`
-		232	`mov ah, 0x19 /* query default (current) disk */`
-		233	`int 0x21 /* drive in AL (0=A, 1=B, etc) */`
-		234	`mov [drv], 1 /* preset result as success */`
-		235	`cmp al, dl /* is eq? */`
-		236	`je DONE`
-		237	`mov [drv], 0 /* fail */`
-		238	`jmp FAILED`
-		239	`DONE:`
-		240	`/* set current drive back to what it was initially */`
-		241	`mov ah, 0x0E`
-		242	`mov dl, ch`
-		243	`int 0x21`
-		244	`FAILED:`
-		245	`}`
-		246	`return(drv);`
-		247	`}`
211		248

Subversion Repositories SvarDOS

(root)/svarcom/trunk/helpers.c – Rev 397 → 399