What might I be doing wrong? Why won't this code succeed to write to
the (otherwise empty) drive 1 from kernel setup's main? I'm 100%
certain this is the code I'm booting (with grub/bzImage); it's as though
the intcalls just never happen (or fail for some reason I can't get
telemetry on, which is why I'm trying this technique in the first place).
--- /var/tmp/main.c 2015-06-30 14:08:52.435618099 -0700
+++ arch/x86/boot/main.c 2015-07-01 20:33:32.227506260 -0700
@@ -132,6 +131,8 @@
}
}
+char block[512] = "DJM WAS HERE ";
+
void main(void)
{
/* First, copy the boot header into the "zeropage" */
@@ -142,6 +143,22 @@
if (cmdline_find_option_bool("debug"))
puts("early console in setup code\n");
+ struct biosregs ireg, oreg;
+ initregs(&ireg);
+ ireg.ah = 0; // reset drive 81
+ ireg.dl = 0x81;
+ intcall(0x13, &ireg, &oreg);
+
+ initregs(&ireg);
+ ireg.ah = 0x03; // write AL sectors to drive DL CHS CH/DH/CL
+ ireg.al = 1;
+ ireg.dl = 0x81;
+ ireg.cl = 1;
+ ireg.dh = 0;
+ ireg.es = ds();
+ ireg.bx = (uint)(uintptr_t)█
+
+ intcall(0x13, &ireg, &oreg);
/* End of heap check */
init_heap();
--
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