Merge pull request #31 from greg-king5/cbm-chain

Commodore exec() function

asminc/c128.inc

@@ -6,6 +6,7 @@
 ; ---------------------------------------------------------------------------
 ; Zero page, Commodore stuff
 
+TXTPTR          := $3D          ; Pointer into BASIC source code
 TIME            := $A0          ; 60HZ clock
 FNAM_LEN        := $B7          ; Length of filename
 SECADR          := $B9          ; Secondary address

asminc/c64.inc

@@ -6,6 +6,7 @@
 ; ---------------------------------------------------------------------------
 ; Zero page, Commodore stuff
 
+TXTPTR          := $7A          ; Pointer into BASIC source code
 TIME            := $A0          ; 60 HZ clock
 FNAM_LEN        := $B7          ; Length of filename
 SECADR          := $B9          ; Secondary address

asminc/cbm510.inc

@@ -3,14 +3,17 @@
 ;
 ; Taken from a kernal disassembly done by myself in 2000/2001.
 ;
-; Ullrich von Bassewitz, 13.09.2001
+; 2001-09-13, Ullrich von Bassewitz
+; 2013-08-26, Greg King
 
 
 ;-----------------------------------------------------------------------------
 ; Zeropage stuff
 
-ExecReg         = $00
+ExecReg         := $00          ; Controls execution memory bank
-IndReg          = $01
+IndReg          := $01          ; Controls indirect indexed load-store bank
+
+TXTPTR          := $85          ; Far pointer into BASIC source code
 
 ; ---------------------------------------------------------------------------
 ; Screen size
@@ -21,7 +24,7 @@ YSIZE           = 25
 ;-----------------------------------------------------------------------------
 ; I/O Definitions
 
-; I/O  $d800: VIC
+; I/O  $d800: VIC-II
 
 VIC_SPR0_X      = $00
 VIC_SPR0_Y      = $01
@@ -75,7 +78,6 @@ VIC_BG_COLOR2   = $23
 VIC_BG_COLOR3   = $24
 
 
-
 ; I/O  $da00: SID 6581
 
 SID_S1Lo        = $00
@@ -112,7 +114,7 @@ SID_Noise       = $1B
 SID_Read3       = $1C
 
 
-; I/O  $db00: CIA 6526 Inter Process Communication
+; I/O  $db00: CIA 6526, Inter Process Communication
 ; I/O  $dc00: CIA 6526
 
 .struct CIA
@@ -176,7 +178,13 @@ SID_Read3       = $1C
 .endstruct
 
 
-; Out video memory address
+;-----------------------------------------------------------------------------
+; Our video memory address
 
-COLOR_RAM   = $D400                     ; System bank
+COLOR_RAM       := $D400        ; System bank
 
+
+;-----------------------------------------------------------------------------
+
+BASIC_BUF       := $FB5E        ; Bank 0 location of command-line
+BASIC_BUF_LEN   = 162           ; Maximum length of command-line

asminc/cbm610.inc

@@ -1,16 +1,19 @@
 ;
-; Zeropage and I/O definitions for the CBM 610
+; Zero page variables and I/O definitions for the CBM 610
 ;
 ; Taken from a kernal disassembly done by myself in 1987.
 ;
-; Ullrich von Bassewitz, 28.09.1998
+; 1998-09-28, Ullrich von Bassewitz
+; 2013-08-26, Greg King
 
 
 ; ---------------------------------------------------------------------------
 ; Zeropage stuff
 
-ExecReg         = $00
+ExecReg         := $00          ; Controls execution memory bank
-IndReg          = $01
+IndReg          := $01          ; Controls indirect indexed load-store bank
+
+TXTPTR          := $85          ; Far pointer into BASIC source code
 
 ; ---------------------------------------------------------------------------
 ; Screen size
@@ -29,7 +32,8 @@ YSIZE           = 25
         DATA    .byte
 .endstruct
 
-; I/O  $db00: CIA 6526 Inter Process Communication
+
+; I/O  $db00: CIA 6526, Inter Process Communication
 ;
 ;       IPCcia          =       $db00
 
@@ -68,7 +72,6 @@ YSIZE           = 25
 ;       cia             =       $dc00
 
 
-
 ; I/O  $dd00: ACIA 6551
 ;
 ;       acia            =       $dd00
@@ -108,3 +111,7 @@ YSIZE           = 25
 ;       tpi2            =       $df00
 
 
+;-----------------------------------------------------------------------------
+
+BASIC_BUF       := $FA5E        ; Bank 1 location of command-line
+BASIC_BUF_LEN   = 162           ; Maximum length of command-line

asminc/pet.inc

@@ -7,6 +7,7 @@
 ; Zero page, Commodore stuff
 
 MEMSIZE         := $34          ; Size of memory installed
+TXTPTR          := $77          ; Pointer into BASIC source code
 TIME            := $8D          ; 60HZ clock
 KEY_COUNT       := $9E          ; Number of keys in input buffer
 RVS             := $9F          ; Reverse flag
@@ -24,6 +25,9 @@ SCR_LINELEN     := $D5          ; Screen line length
 CURS_Y          := $D8          ; Cursor row
 FNADR           := $DA          ; Pointer to file name
 
+BASIC_BUF       := $200         ; Location of command-line
+BASIC_BUF_LEN   = 81            ; Maximum length of command-line
+
 KEY_BUF         := $26F         ; Keyboard buffer
 
 ;----------------------------------------------------------------------------

asminc/plus4.inc

@@ -7,6 +7,7 @@
 ; Zero page, Commodore stuff
 
 TMPPTR          := $22          ; Temporary ptr used by BASIC
+TXTPTR          := $3B          ; Pointer into BASIC source code
 TIME            := $A3          ; 60HZ clock
 FNAM_LEN        := $AB          ; Length of filename
 LFN             := $AC          ; Logical file number

asminc/vic20.inc

@@ -6,6 +6,7 @@
 ; ---------------------------------------------------------------------------
 ; Zero page, Commodore stuff
 
+TXTPTR          := $7A          ; Pointer into BASIC source code
 TIME            := $A0          ; 60HZ clock
 FNAM_LEN        := $B7          ; Length of filename
 SECADR          := $B9          ; Secondary address

libsrc/cbm/exec.c

@@ -0,0 +1,99 @@
+/*
+** Program-chaining function for Commodore platforms.
+**
+** 2013-08-24, Greg King
+**
+** This function exploits the program-chaining feature in CBM BASIC's ROM.
+** It puts the desired program's name and unit number into a LOAD statement.
+** Then, it points BASIC to that statement, so that the ROM will run that
+** statement after this program quits.  The ROM will load the next program,
+** and will execute it (because the LOAD will be seen in a running program).
+*/
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <device.h>
+#if   defined(__CBM610__)
+#  include <cbm610.h>
+#elif defined(__CBM510__)
+#  include <cbm510.h>
+#endif
+
+
+#pragma data-name(push, "LOWCODE")
+static struct line {
+    const char end_of_line;
+    const struct line *const next;
+    const unsigned line_num;
+    const char load_token, quotes[2], add_token, quote;
+    char name[21];
+    const char comma;
+    char unit[3];
+} basic = {
+    '\0', &basic + 1,           /* high byte must be non-zero */
+    0, 0x93,
+
+    /* This string operation copies the name to high BASIC RAM.
+    ** So, it won't be overwritten when the next program is loaded.
+    */
+    "\"\"", 0xaa, '\"',
+    "\"                    ",   /* format: "123:1234567890123456\"" */
+    ',', "01"
+};
+#pragma data-name(pop)
+
+/* These values are platform-specific. */
+extern const struct line *txtptr;
+#pragma zpsym("txtptr")
+extern char basbuf[];           /* BASIC's input buffer */
+extern void basbuf_len[];
+#pragma zpsym("basbuf_len")
+
+
+int __fastcall__ exec (const char* progname, const char* cmdline)
+{
+    static int fd;
+    static unsigned char dv, n = 0;
+
+    /* Exclude devices that can't load files. */
+    dv = getcurrentdevice ();
+    if (dv < 8 && dv != 1 || dv > 30) {
+        return _mappederrno (9);        /* illegal device number */
+    }
+    utoa (dv, basic.unit, 10);
+
+    /* Don't try to run a program that can't be found. */
+    fd = open (progname, O_RDONLY);
+    if (fd < 0) {
+        return fd;
+    }
+    close (fd);
+
+    do {
+        if ((basic.name[n] = progname[n]) == '\0') {
+            break;
+        }
+    } while (++n < 20);         /* truncate long names */
+    basic.name[n] = '\"';
+
+    /* Build the next program's argument list. */
+    basbuf[0] = 0x8f;           /* REM token */
+    basbuf[1] = '\0';
+    if (cmdline != NULL) {
+        strncat (basbuf, cmdline, (size_t)basbuf_len - 2);
+    }
+
+#if defined(__CBM510__) || defined(__CBM610__)
+    pokewsys ((unsigned)&txtptr, (unsigned)&basic);
+#else
+    txtptr = &basic;
+#endif
+
+    /* (The return code, in ST, will be destroyed by LOAD.
+    ** So, don't bother to set it here.)
+    */
+    exit (__AX__);
+}

libsrc/cbm/execvars.s

@@ -0,0 +1,28 @@
+;
+; Platform-specific variables for the exec program-chaining function
+;
+
+.if     .defined (__C128__)
+        .include        "c128.inc"
+.elseif .defined (__C16__)
+        .include        "c16.inc"
+.elseif .defined (__C64__)
+        .include        "c64.inc"
+.elseif .defined (__CBM510__)
+        .include        "cbm510.inc"
+.elseif .defined (__CBM610__)
+        .include        "cbm610.inc"
+.elseif .defined (__PET__)
+        .include        "pet.inc"
+.elseif .defined (__PLUS4__)
+        .include        "plus4.inc"
+.else
+        .include        "vic20.inc"
+.endif
+
+        .export         _txtptr:zp, _basbuf, _basbuf_len:zp
+
+_txtptr         :=      TXTPTR
+
+_basbuf         :=      BASIC_BUF
+_basbuf_len     =       BASIC_BUF_LEN

libsrc/pet/mainargs.s

@@ -13,7 +13,6 @@
 MAXARGS  = 10                   ; Maximum number of arguments allowed
 REM      = $8f                  ; BASIC token-code
 NAME_LEN = 16                   ; maximum length of command-name
-BASIC_BUF= $200
 
 
 ;---------------------------------------------------------------------------

testcode/lib/arg-test.c

@@ -9,6 +9,9 @@ int main (int argc, char* argv[])
     for (I = 0; I < argc; ++I) {
         printf ("argv[%2d]: \"%s\"\n", I, argv[I]);
     }
+
+    printf ("\n");
+    getchar ();
     return EXIT_SUCCESS;
 }
 

testcode/lib/exec-test1.c

@@ -0,0 +1,24 @@
+/*
+** These programs test CC65's exec() program-chaining function.
+** exec-test1 runs exec-test2 -- that tests the loading and starting of another
+** program.  Then, exec-test2 runs arg-test -- that tests command-line argument
+** passing.
+**
+** 2013-08-24, Greg King
+*/
+
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <conio.h>
+
+int main (void) {
+    clrscr ();
+    cprintf ("\nExec-test #1 -- launching #2...\r\n");
+
+    exec ("exec-test2", "");
+
+    cprintf ("\nFailed to find #2:\r\n %s.\r\n", _stroserror (_oserror));
+    cgetc ();
+    return _oserror;
+}

testcode/lib/exec-test2.c

@@ -0,0 +1,23 @@
+/*
+** These programs test CC65's exec() program-chaining function.
+** exec-test1 runs exec-test2 -- that tests the loading and starting of another
+** program.  Then, exec-test2 runs arg-test -- that tests command-line argument
+** passing.
+**
+** 2013-08-24, Greg King
+*/
+
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <conio.h>
+
+int main (void) {
+    cprintf ("\nExec-test #2 -- launching arg-test...\r\n\n");
+
+    exec ("arg-test", "arg1 arg2 \"\" arg4");
+
+    cprintf ("\nFailed to find arg-test:\r\n %s.\r\n", _stroserror (_oserror));
+    cgetc ();
+    return _oserror;
+}