aline with agn453 hitech C

tsupplis · Mar 28, 2022 · 363cfce · 363cfce
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commit 363cfce
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Showing 4 changed files with 59 additions and 30 deletions.
diff --git a/close.c b/close.c
@@ -2,32 +2,44 @@
 /*
     This is a modified version of close.c to support exact file sizes.
 
-    Unfortunately there are two common conventions used to record the exact size in CP/M.
+    Unfortunately there are two common conventions used to record the
+    exact size in CP/M.
+
     1) Record the bytes used in the last sector - used by DOSPLUS
-    2) Record the bytes unused in the last sector - used by ISX for ISIS emulation
+    2) Record the bytes unused in the last sector - used by ISX for
+       ISIS emulation
 
     A previous version of this file only supported convention 2.
 
-    To support both of these variants an environment variable EXACT is used.
-    Hi-Tech C supports this through the use of a file ENVIRON
-    The values for EXACT are noted below, but in reality only the first
-    character is checked.
-    EXACT=DOSPLUS     This uses convention 1 above
-    EXACT=ISX         This uses convention 2 above
-    if EXACT is not defined or doesn't start with a 'D' or 'I', exact file size
-    isn't used.
+    To support both of these variants, a global variable _exact is
+    set-up by the start-up module.
+
+    The values for _exact are noted below
+
+    'D' for DOSPLUS     This uses convention 1 above
+    'I' for ISIS/ISX    This uses convention 2 above
+    'C' for CP/M 2      Exact file size is not used
+
+    Under CP/M 3 this defaults to 'D' DOSplus mode.  If you wish
+    to use ISIS mode, you must set _exact to 'I' prior to using
+    file I/O routines - e.g.
 
-    Note you need to take extra care in setting EXACT if you are using an emulator
-    that can access host files and truncates files to match the exact size.
-    Using the wrong mode will mean that the value this function passes to the emulator
-    will be wrong and could result in data losss. If in doubt I recommend exact size isn't used.
+        extern char _exact;
 
-    For the ZXCC emulator, using EXACT=DOSPLUS is safe.
+        _exact = 'I';
+
+    Note you need to take extra care with _exact if you are using an
+    emulator that can access host files and truncates files to match
+    the exact size.  Using the wrong mode will mean that the value
+    this function passes to the emulator will be wrong and could
+    result in data losss. If in doubt I recommend exact size isn't used.
+
+    For the ZXCC emulator, using _exact as 'D' is safe.
 */
 
-static char exact = 0;  /* 0 = not determined, 'C' = not used (old CP/M),
-                           'D' = DOSPLUS mode,  'I' = ISX mode
-                        */
+extern char _exact;  /* 'C' = not used (old CP/M),
+                        'D' = DOSPLUS mode,  'I' = ISX mode
+                      */
 
 char *getenv(char *);
 int toupper(int );
@@ -36,7 +48,6 @@ int close(uchar fd)
 {
     register struct fcb *fc;
     uchar       luid;
-    char *env;
 
     if (fd >= MAXFILE)
         return -1;
@@ -46,14 +57,8 @@ int close(uchar fd)
     if (fc->use == U_WRITE || fc->use == U_RDWR
                            || bdos(CPMVERS)&(MPM|CCPM) && fc->use == U_READ)
         bdos(CPMCLS, fc);
-    if (!exact) { /* get the exact size mode, checking only once */
-        if ((env = getenv("EXACT")))
-            exact = toupper(*env);
-        if (exact != 'I' && exact != 'D')
-            exact = 'C';
-    }
-    if (exact != 'C') { /* skip if old CP/M mode */
-        fc->nr = (exact == 'D' ? fc->fsize : -fc->fsize) & 0x7f;  /* Set exact file size */
+    if (_exact != 'C') { /* skip if old CP/M mode */
+        fc->nr = (_exact == 'D' ? fc->fsize : -fc->fsize) & 0x7f; /* Set exact file size */
         fc->name[5] |= 0x80;
         if (fc->use == U_WRITE || fc->use == U_RDWR)
             bdos(CPMSATT, fc);

diff --git a/testver.c b/testver.c
@@ -2,6 +2,8 @@
 #include "cpm.h"
 #include <stdio.h>
 
+extern char _exact;	/* exact file size mode */
+
 int main(int argc, char ** argv)
 {
     int i;
@@ -49,6 +51,21 @@ int main(int argc, char ** argv)
     printf("BIOS Address (0x%04x)\n",*biosaddr-3);
     tpa=((*bdosaddr-6)-0x100);
     fprintf(stdout,"TPA Size (%u.%uK)\n",tpa/1024,(tpa % 1024)/100);
+
+    switch(_exact) {
+    case 'C':
+        printf("Exact file size not used (CP/M 2 mode)\n");
+        break;
+    case 'D':
+        printf("Using DOS Plus exact file size mode\n");
+        break;
+    case 'I':
+        printf("Using ISIS exact file size mode\n");
+    default:
+        printf("Unknown exact file size mode 0%xH\n",_exact);
+        break;
+    }
+
     return 0;
 }
 
diff --git a/zcrtcpm.as b/zcrtcpm.as
@@ -6,7 +6,7 @@
 	defs	100h		;Base of CP/M's TPA
 
 	global	start,_main,_exit,__Hbss, __Lbss, __argc_, __z3env, startup
-    global  __piped,__initrsx, _getenv
+        global  __piped,__initrsx,__exact
 
 start:		; DOS Protection	8080/Z80	x86
 				;	---------  --------------------
@@ -99,9 +99,12 @@ memok:
 	xor	a		; CP/M 2.2 has no RSX
 	jr	norsx
 
+iscpm3:	ld	hl,__exact	; Default exact file size
+	inc	(hl)		;  to DOSplus mode ('C' becomes 'D')
+
 ;If the PIPEMGR RSX is loaded, initialise it.
 
-iscpm3:	ld	c,60		; RSX call
+	ld	c,60		; RSX call
 	ld	de,rsxpb	; RSX data
 	call	5
 	ld	a,h
@@ -152,6 +155,8 @@ __z3env:
 	defw	0
 __piped:
         defw    0
+__exact:		; Exact file size mode
+	defb	'C',0	; 'C' is CP/M 2 (none), 'I' is ISIS, 'D' is DOSPLUS
 rsxpb:	defb	79h,1
 	defw	pipesgn
 pipesgn:

diff --git a/zrrtcpm.as b/zrrtcpm.as
@@ -12,7 +12,7 @@
 	psect	cpm
 	defs	100h		;Base of CP/M's TPA
 	global	start,_main,_exit,__Lbss,__Hstack, __z3env
-	global	__piped,__initrsx, _getenv
+	global	__piped,__initrsx,__exact
 
 
 reloc:		; DOS Protection	8080/Z80	x86
@@ -235,6 +235,8 @@ __z3env:
 	defw	0
 __piped:
         defw    0
+__exact:		; Exact file size mode
+	defb	'C',0	; 'C' is CP/M 2 (none), 'I' is ISIS, 'D' is DOSPLUS
 rsxpb:	defb	79h,1
 	defw	pipesgn
 pipesgn: