gfxboot: align buffers and move them into bss

Align I/O buffers to a multiple of 512 bytes, as required by the
Syslinux ABI.  Furthermore, move them from data to bss, so that they
don't occupy space in the image file.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Sebastian Herbszt <herbszt@gmx.de>

diff --git a/modules/Makefile b/modules/Makefile
index 3ae463f..2668be8 100644 (file)
--- a/modules/Makefile
+++ b/modules/Makefile
@@ -50,7 +50,7 @@ $(LIB): $(LIBOBJS)
        $(PNGTOPNM) $< | gzip -9 > $@
 
 tidy dist:
-       rm -f *.o *.a *.lst *.elf .*.d
+       rm -f *.o *.a *.lst *.elf *.map .*.d
 
 clean: tidy
 

diff --git a/modules/gfxboot.asm b/modules/gfxboot.asm
index e3aed13..af1c6b5 100644 (file)
--- a/modules/gfxboot.asm
+++ b/modules/gfxboot.asm
@@ -20,6 +20,8 @@
 ;
 ; ****************************************************************************
 
+               [map all gfxboot.map]
+
                absolute 0
 pspInt20:      resw 1
 pspNextP:      resw 1
@@ -33,6 +35,15 @@ pspCmdArg:   resb 127
                org 100h
 
 _start:
+               ; Zero memory from the start of .bss to the stack
+               cld
+               mov di,section..bss.start
+               mov cx,sp
+               sub cx,di
+               shr cx,2
+               xor eax,eax
+               rep stosd
+
                mov ax,2
                mov bx, msg_progname
                int 22h
@@ -866,23 +877,8 @@ memcmp:
                ret
 
                section .data
-derivative_id          db 0
-drivenumber            db 0
-sectorshift            db 0
-sectorsize             dw 0
-trackbufsize           equ 16384
-trackbuf               times trackbufsize db 0
-BufSafe                        dw 0
-file_length            dd 0
-
-bufbytes               dw 0
-bufdata                        dw 0
-configbuf              times trackbufsize db 0
-ungetc_cnt             db 0
-ungetcdata             db 0
 label_keyword          db 6,'label',0
 default_keyword                db 7,'default',0
-label_cnt              dw 0
 
 msg_progname           db 'gfxboot: ',0
 msg_config_file                db 'Configuration file',0
@@ -895,16 +891,8 @@ msg_unknown_file_size      db 'unknown file size',0dh,0ah,0
 msg_space              db ' ',0
 msg_crlf               db 0dh,0ah,0
 
-f_handle               dw 0
-f_size                 dd 0
-fname_buf              times 64 db 0
-fname_buf_len          equ $ - fname_buf
 gfx_slash              db '/', 0
 db0                    db 0
-max_cmd_len  equ 2047
-command_line           times max_cmd_len+2 db 0
-dentry_buf             times 512 db 0
-dentry_buf_len         equ $ - dentry_buf
 
 ; menu entry descriptor
 menu_entries           equ 0
@@ -915,26 +903,6 @@ menu_arg_list              equ 12          ; seg:ofs
 menu_arg_size          equ 16
 sizeof_menu_desc       equ 18
 
-menu_desc              times sizeof_menu_desc db 0
-menu_seg               dw 0
-menu_off               dw 0
-
-gfx_mem_start_seg      dw 0
-gfx_mem_end_seg                dw 0
-
-                       align 4, db 0
-gfx_mem                        dd 0            ; linear address
-gfx_save_area1         dd 0            ; 64k
-gfx_save_area1_used    db 0            ; != 0 if area1 is in use
-
-; interface to loadable gfx extension (seg:ofs values)
-gfx_bc_jt              dd 0
-
-gfx_bc_init            dd 0
-gfx_bc_done            dd 0
-gfx_bc_input           dd 0
-gfx_bc_menu_init       dd 0
-
 ; system config data (52 bytes)
 gfx_sysconfig          equ $
 gfx_bootloader         db 1                    ;  0: boot loader type (0: lilo, 1: syslinux, 2: grub)
@@ -962,3 +930,56 @@ gfx_archive_end            dd 0                    ; 40: end of cpio archive
 gfx_mem0_start         dd 0                    ; 44: low free memory start
 gfx_mem0_end           dd 0                    ; 48: low free memory end
 gfx_sysconfig_end      equ $
+
+                       section .bss align=512
+trackbufsize           equ 16384
+trackbuf               resb trackbufsize
+configbuf              resb trackbufsize
+
+dentry_buf             resb 512
+dentry_buf_len         equ $ - dentry_buf
+
+max_cmd_len            equ 2047
+command_line           resb max_cmd_len+2
+
+                       alignb 4
+derivative_id          resb 1
+drivenumber            resb 1
+sectorshift            resb 1
+                       resb 1                  ; Pad
+sectorsize             resw 1
+BufSafe                        resw 1
+file_length            resd 1
+
+bufbytes               resw 1
+bufdata                        resw 1
+ungetc_cnt             resb 1
+ungetcdata             resb 1
+
+f_handle               resw 1
+f_size                 resd 1
+fname_buf              resb 64
+fname_buf_len          equ $ - fname_buf
+
+label_cnt              resw 1
+
+menu_desc              resb sizeof_menu_desc
+menu_seg               resw 1
+menu_off               resw 1
+
+gfx_mem_start_seg      resw 1
+gfx_mem_end_seg                resw 1
+
+                       alignb 4
+gfx_mem                        resd 1          ; linear address
+gfx_save_area1         resd 1          ; 64k
+gfx_save_area1_used    resb 1          ; != 0 if area1 is in use
+
+                       alignb 4
+; interface to loadable gfx extension (seg:ofs values)
+gfx_bc_jt              resd 1
+
+gfx_bc_init            resd 1
+gfx_bc_done            resd 1
+gfx_bc_input           resd 1
+gfx_bc_menu_init       resd 1