[prefix] Add rudimentary debugging messages to libprefix

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/arch/i386/prefix/libprefix.S b/src/arch/i386/prefix/libprefix.S
index f95a7a1ff7e233f567eb57294cfd905fc80a68b4..b67798e5d5f8cdf0928d33946dc593e7c2ac2c53 100644 (file)
--- a/src/arch/i386/prefix/libprefix.S
+++ b/src/arch/i386/prefix/libprefix.S
@@ -27,6 +27,33 @@ FILE_LICENCE ( GPL2_OR_LATER )
 /* Protected mode flag */
 #define CR0_PE 1
 
+/* Allow for DBG()-style messages within libprefix */
+#ifdef NDEBUG
+       .macro  progress message
+       .endm
+#else
+       .macro  progress message
+       pushfl
+       pushw   %ds
+       pushw   %si
+       pushw   %di
+       pushw   %cs
+       popw    %ds
+       xorw    %di, %di
+       movw    $progress_\@, %si
+       call    print_message
+       popw    %di
+       popw    %si
+       popw    %ds
+       popfl
+       .section ".prefix.data", "aw", @progbits
+progress_\@:
+       .asciz  "\message"
+       .size   progress_\@, . - progress\@
+       .previous
+       .endm
+#endif
+
 /*****************************************************************************
  * Utility function: print character (with LF -> LF,CR translation)
  *
@@ -583,6 +610,7 @@ hooked_bios_interrupts:
        .code16
        .globl install
 install:
+       progress "install:\n"
        /* Preserve registers */
        pushl   %esi
        pushl   %edi
@@ -621,6 +649,7 @@ install:
        .code16
        .globl install_prealloc
 install_prealloc:
+       progress "install_prealloc:\n"
        /* Save registers */
        pushal
        pushw   %ds
@@ -636,6 +665,7 @@ install_prealloc:
        movl    %edi, %ebp
 
        /* Install .text16.early */
+       progress "  .text16.early\n"
        pushl   %esi
        xorl    %esi, %esi
        movw    %cs, %si
@@ -653,6 +683,7 @@ install_prealloc:
         * already have 4GB segment limits as a result of calling
         * install_block.)
         */
+       progress "  access_highmem\n"
        pushw   %cs
        pushw   $1f
        pushw   %ax
@@ -673,6 +704,7 @@ a20_death_message:
 #endif
 
        /* Open payload (which may not yet be in memory) */
+       progress "  open_payload\n"
        pushw   %cs
        pushw   $1f
        pushw   %ax
@@ -701,9 +733,11 @@ payload_death_message:
 1:     addl    payload_lma, %esi
 
        /* Install .text16.late and .data16 */
+       progress "  .text16.late\n"
        movl    $_text16_late_filesz, %ecx
        movl    $_text16_late_memsz, %edx
        call    install_block           /* .text16.late */
+       progress "  .data16\n"
        movzwl  %bx, %edi
        shll    $4, %edi
        movl    $_data16_filesz, %ecx
@@ -738,12 +772,14 @@ payload_death_message:
         * prior to reading the E820 memory map and relocating
         * properly.
         */
+       progress "  .textdata\n"
        movl    %ebp, %edi
        movl    $_textdata_filesz, %ecx
        movl    $_textdata_memsz, %edx
        call    install_block
 
        /* Initialise librm at current location */
+       progress "  init_librm\n"
        movw    %ax, (init_librm_vector+2)
        movl    %ebp, %edi
        lcall   *init_librm_vector
@@ -757,12 +793,14 @@ payload_death_message:
         * relocate() will return with %esi, %edi and %ecx set up
         * ready for the copy to the new location.
         */
+       progress "  relocate\n"
        movw    %ax, (prot_call_vector+2)
        pushl   $relocate
        lcall   *prot_call_vector
        popl    %edx /* discard */
 
        /* Copy code to new location */
+       progress "  copy\n"
        pushl   %edi
        pushw   %bx
        movw    $copy_bytes, %bx
@@ -771,11 +809,13 @@ payload_death_message:
        popl    %edi
 
        /* Initialise librm at new location */
+       progress "  init_librm\n"
        lcall   *init_librm_vector
 skip_relocate:
 #endif
 
        /* Close access to payload */
+       progress "  close_payload\n"
        movw    %ax, (close_payload_vector+2)
        lcall   *close_payload_vector