Towards making KEEP_IT_REAL work again.

[gpxe.git] / src / arch / i386 / transitions / libkir.S

diff --git a/src/arch/i386/transitions/libkir.S b/src/arch/i386/transitions/libkir.S
index e0d6c57..1023ddd 100644 (file)
--- a/src/arch/i386/transitions/libkir.S
+++ b/src/arch/i386/transitions/libkir.S
@@ -34,6 +34,23 @@
        .section ".text16", "awx", @progbits
        .code16
        
+/****************************************************************************
+ * init_libkir (real-mode or 16:xx protected-mode far call)
+ *
+ * Initialise libkir ready for transitions to the kir environment
+ *
+ * Parameters:
+ *   %cs : .text16 segment
+ *   %ds : .data16 segment
+ ****************************************************************************
+ */
+       .globl  init_libkir
+init_libkir:
+       /* Record segment registers */
+       pushw   %ds
+       popw    %cs:kir_ds
+       lret
+       
 /****************************************************************************
  * ext_to_kir (real-mode or 16:xx protected-mode near call)
  *
@@ -45,10 +62,6 @@
  * %cs:0000 must point to the start of the runtime image code segment
  * on entry.
  *
- * Note that this routine can be called *without* having first set up
- * a stored kir_ds and kir_sp.  If you do this, ext_to_kir will return
- * without altering the segment registers or stack pointer.
- *
  * Parameters: none
  ****************************************************************************
  */
@@ -73,10 +86,8 @@ ext_to_kir:
        movw    %ss, %ds:ext_ss
        movl    %esp, %ds:ext_esp
 
-       /* Load internal segment registers and stack pointer, if available */
+       /* Load internal segment registers and stack pointer */
        movw    %ds:kir_ds, %ax
-       testw   %ax, %ax
-       jz      1f
        movw    %ax, %ss
        movzwl  %ds:kir_sp, %esp
        movw    %ax, %ds
@@ -144,12 +155,12 @@ kir_to_ext:
  * will also be preserved.
  *
  * Parameters:
- *   function : (16-bit) virtual address of protected-mode function to call
+ *   function : (32-bit) virtual address of C function to call
  *
  * Example usage:
- *     pushw   $pxe_api_call
+ *     pushl   $pxe_api_call
  *     lcall   $UNDI_CS, $kir_call
- *     addw    $2, %sp
+ *     addw    $4, %sp
  * to call in to the C function
  *      void pxe_api_call ( struct i386_all_regs *ix86 );
  ****************************************************************************
@@ -157,7 +168,6 @@ kir_to_ext:
 
        .globl  kir_call
 kir_call:
-
        /* Preserve flags.  Must do this before any operation that may
         * affect flags.
         */
@@ -174,8 +184,8 @@ kir_call:
         * either a 16-bit or a 32-bit stack segment.
         */
        popl    %cs:save_retaddr        /* Scratch location */
-       popw    %cs:save_function
-       subl    $6, %esp                /* Restore %esp */
+       popl    %cs:save_function
+       subl    $8, %esp                /* Restore %esp */
        
        /* Switch to internal stack.  Note that the external stack is
         * inaccessible once we're running internally (since we have
@@ -191,6 +201,7 @@ kir_call:
        pushl   %cs:ext_cs_and_ss
 
        /* Push &ix86 on stack and call function */
+       sti
        pushl   %esp
        data32 call *%cs:save_function
        popl    %eax /* discard */
@@ -231,13 +242,13 @@ ext_esp:  .long 0
                .globl kir_ds
 kir_ds:                .word 0
                .globl kir_sp
-kir_sp:                .word 0
+kir_sp:                .word _estack
 
 /****************************************************************************
  * Temporary variables
  ****************************************************************************
  */
 save_ax:       .word 0
-save_retaddr:  .word 0
+save_retaddr:  .long 0
 save_flags:    .long 0
 save_function: .long 0