diag/mbr/handoff: Add optional printing of floppy descriptor

diff --git a/diag/mbr/handoff.S b/diag/mbr/handoff.S
index 2ac0ccc..7af3fde 100644 (file)
--- a/diag/mbr/handoff.S
+++ b/diag/mbr/handoff.S
@@ -56,6 +56,7 @@
 #define DEBUG_PNP      /* Scan for $PnP and show address */
 #define DEBUG_PAK      /* Press Any Key before boot fail */
 // #define DEBUG_ENTRY_REG     /* Store (manually as pusha is 80186) registers */
+// #define DEBUG_FDT   /* Print the floppy descriptor table; INT 1Eh*/
 
 #ifdef DEBUG_MARKER1
        .macro ASCII_MARKER1 s:vararg
@@ -108,6 +109,10 @@ es_bot             = (es_ds)
 
 BIOS_page      = 0x462
 
+int_1e         = (4*0x1e)
+int_1e_seg     = (int_1e)
+int_1e_off     = (int_1e+2)
+
        .globl  _start
 _start:
        cli
@@ -247,6 +252,27 @@ pr_pnp:
        call    crlf
 pnp_end:
 
+#ifdef DEBUG_FDT
+       /* INT 1Eh: Floppy Parameter Table Pointer */
+pr_1e: call    wrstr
+       .ascii  "INT 1Eh: \0"
+       mov     $int_1e,%bx
+       les     (%bx),%di
+       pushw   %es
+       popw    %dx
+       call    wrhexw
+       movb    $':, %al
+       call    wrchr
+       pushw   %di
+       popw    %dx
+       call    wrhexw
+       call    crlf
+       /* [INT 1Eh] */
+       movw    $14, %cx
+       call    wrhexbses
+       call    crlf
+#endif /* DEBUG_FDT */
+
 end:
        jmp     bootfail