syscall_exec: further work - mostly to persuade sdcc to generate passable code

diff --git a/Kernel/syscall_exec.c b/Kernel/syscall_exec.c
index 05ce87c..bab71b4 100644 (file)
--- a/Kernel/syscall_exec.c
+++ b/Kernel/syscall_exec.c
@@ -16,7 +16,7 @@ static int bload(inoptr i, uint16_t bl, uint16_t base, uint16_t len)
                        uint8_t *buf;
                        buf = bread(i->c_dev, blk, 0);
                        if (buf == NULL) {
-                               kprintf("bload failed.\n");
+                               kputs("bload failed.\n");
                                return -1;
                        }
                        uput(buf, (uint8_t *)base, cp);
@@ -29,7 +29,7 @@ static int bload(inoptr i, uint16_t bl, uint16_t base, uint16_t len)
                        udata.u_count = 512;
                        udata.u_base = (uint8_t *)base;
                        if (cdread(i->c_dev, 0) < 0) {
-                               kprintf("bload failed.\n");
+                               kputs("bload failed.\n");
                                return -1;
                        }
 #endif
@@ -68,12 +68,13 @@ int16_t _execve(void)
        staticfast unsigned char *buf;
        char **nargv;           /* In user space */
        char **nenvp;           /* In user space */
-       staticfast struct s_argblk *abuf, *ebuf;
+       struct s_argblk *abuf, *ebuf;
        int argc;
        uint16_t progptr;
        staticfast uint16_t top;
-       uint16_t bin_size;
-       uint16_t bss = 0;
+       uint16_t bin_size;      /* Will need to be bigger on some cpus */
+       uint16_t bss;
+       char *p;
 
        top = ramtop;
 
@@ -91,7 +92,7 @@ int16_t _execve(void)
 
        if (ino->c_node.i_size == 0) {
                udata.u_error = ENOEXEC;
-               goto nogood2;
+               goto nogood;
        }
 
        /* Read in the first block of the new program */
@@ -115,16 +116,19 @@ int16_t _execve(void)
         *      wrap the binaries and do the emulator load so we can clean up
         *      all the kernel code for this case). We don't really want to end
         *      up with CP/M, o65 and other emulations in kernel!
+        *
+        *      Use p to persuade sdcc not to generate shite code
         */
-       if (buf[3] != 'F' || buf[4] != 'Z' || buf[5] != 'X' || buf[6] != '1' ||
+       p = buf + 3;
+
+       if (*p++ != 'F' || *p++ != 'Z' || *p++ != 'X' || *p++ !='1' || 
                /* Don't load binaries for the wrong base page, eg spectrum
                   binaries on a sane box. 0 indicates a relocatable binary */
-               (buf[7] && buf[7] != PROGLOAD >> 8)) {
+               (*p && *p != PROGLOAD >> 8)) {
                udata.u_error = ENOEXEC;
                goto nogood2;
        }
-
-       top = buf[8] | ((unsigned int)buf[9] << 8);
+       top = *++p + (*p << 8);
        if (top == 0)   /* Legacy 'all space' binary */
                top = ramtop;
        else    /* Requested an amount, so adjust for the base */
@@ -133,12 +137,13 @@ int16_t _execve(void)
        bss = buf[14] | (buf[15] << 8);
 
        /* Binary doesn't fit */
-       if (top - PROGBASE < ino->c_node.i_size + 1024 + bss) {
+       bin_size = ino->c_node.i_size;
+       progptr = bin_size + 1024 + bss;
+       if (top - PROGBASE < progptr || progptr < bin_size) {
                udata.u_error = ENOMEM;
                goto nogood2;
        }
 
-       bin_size = ino->c_node.i_size;
 
        /* Gather the arguments, and put them in temporary buffers. */
        abuf = (struct s_argblk *) tmpbuf();