[syslinux] Custom com32

[H. Peter Anvin]

Coe, Colin C. (Unix Engineer) wrote:
> OK, stupid question time.  How do I specify the initrd? Currently I do:
> 
>         strcpy((char *)__com32.cs_bounce, array_model[i]);
>         strcat((char *)__com32.cs_bounce, "_");
>         strcat((char *)__com32.cs_bounce, array_bios[i]);
>         strcat((char *)__com32.cs_bounce, ".img");
> 
>         memset(&reg, 0, sizeof reg);
>         reg.eax.w[0] = 0x0003;
>         reg.ebx.w[0] = OFFS(__com32.cs_bounce);
>         reg.es       = SEG(__com32.cs_bounce);
> 
>         #ifdef DEBUG
>         printf("About to boot image %s\n", (char *)__com32.cs_bounce);
>         fgets(buffer, sizeof buffer, stdin);
>         #endif
>         __intcall(0x22, &reg, &reg);
> 
>         if ( reg.eflags.l & EFLAGS_CF )
>           return 0;
>         else
>           return reg.eax.l;
> 

Something like:

char *bptr = __com32.cs_bounce;
char *image, *cmdline;

image = bptr;
bptr += sprintf(bptr, "memdisk");	/* Kernel image */
bptr++;					/* Terminal null */
cmdline = bptr;
bptr += sprintf(bptr, "initrd=%s_%s.img", array_model, array_bios);

memset(&reg, 0, sizeof reg);
reg.eax.w[0] = 0x0016;
reg.esi.w[0] = OFFS(image);
reg.ds       = SEG(image);
reg.ebx.w[0] = OFFS(cmdline);
reg.es       = SEG(cmdline);

__intcall(0x22, &reg, &reg);

return (reg.eflags.l & EFLAGS_CF) ? -1 : 0;