syscall_exec16: still trying to get sdcc to generate non-crap code for this

diff --git a/Kernel/syscall_exec16.c b/Kernel/syscall_exec16.c
index aea4876..e84c72a 100644 (file)
--- a/Kernel/syscall_exec16.c
+++ b/Kernel/syscall_exec16.c
@@ -62,10 +62,32 @@ char *envp[];
 #define argv (char **)udata.u_argn1
 #define envp (char **)udata.u_argn2
 
+/* Magic numbers
+
+       0xC3 xx xx      - Z80 with 0x100 entry
+       0x4C xx xx      - 6502
+       0x0E xx xx      - 6809
+
+   followed by a base page for the executable
+
+*/
+static int header_ok(uint8_t *pp)
+{
+       register uint8_t *p = pp;
+       if (*p != EMAGIC && *p != EMAGIC_2)
+               return 0;
+       p += 3;
+       if (*p++ != 'F' || *p++ != 'Z' || *p++ != 'X' || *p++ != '1')
+               return 0;
+       if (*p && *p != (PROGLOAD >> 8))
+               return 0;
+       return 1;
+}
+
 arg_t _execve(void)
 {
        staticfast inoptr ino;
-       staticfast unsigned char *buf;
+       unsigned char *buf;
        char **nargv;           /* In user space */
        char **nenvp;           /* In user space */
        struct s_argblk *abuf, *ebuf;
@@ -74,7 +96,6 @@ arg_t _execve(void)
        staticfast uint16_t top;
        uint16_t bin_size;      /* Will need to be bigger on some cpus */
        uint16_t bss;
-       uint8_t *p;
 
        top = ramtop;
 
@@ -98,43 +119,17 @@ arg_t _execve(void)
        /* Read in the first block of the new program */
        buf = bread(ino->c_dev, bmap(ino, 0, 1), 0);
 
-       /* Magic numbers
-               0xC3 xx xx      - Z80 with 0x100 entry
-               0x4C xx xx      - 6502
-               0x0E xx xx      - 6809
-
-          followed by a base page for the executable
-
-       */
-       if (*buf  != EMAGIC && *buf != EMAGIC_2) {
+       if (!header_ok(buf)) {
                udata.u_error = ENOEXEC;
                goto nogood2;
        }
-
-       /*
-        *      Executables must be in FUZIX format (we'll let the CP/M emul
-        *      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
-        */
-       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 */
-               (*p && *p != PROGLOAD >> 8)) {
-               udata.u_error = ENOEXEC;
-               goto nogood2;
-       }
-       top = *++p + (*p << 8);
+       top = *(uint16_t *)(buf + 8);
        if (top == 0)   /* Legacy 'all space' binary */
                top = ramtop;
        else    /* Requested an amount, so adjust for the base */
                top += PROGLOAD;
 
-       bss = buf[14] | (buf[15] << 8);
+       bss = *(uint16_t *)(buf + 14);
 
        /* Binary doesn't fit */
        bin_size = ino->c_node.i_size;
@@ -144,7 +139,6 @@ arg_t _execve(void)
                goto nogood2;
        }
 
-
        /* Gather the arguments, and put them in temporary buffers. */
        abuf = (struct s_argblk *) tmpbuf();
        /* Put environment in another buffer. */