Move sysvars definitions to the linker script

This may allow to move the BSS segment anywhere.
vinriviere · Jan 21, 2017 · b07c2e7 · b07c2e7
1 parent 7152c60
commit b07c2e7
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Showing 5 changed files with 144 additions and 224 deletions.
diff --git a/Makefile b/Makefile
@@ -388,7 +388,7 @@ version:
 
 TOCLEAN += obj/*.ld
 
-obj/emutospp.ld: emutos.ld
+obj/emutospp.ld: emutos.ld tosvars.ld
 	$(CPP) $(CPPFLAGS) -P -x c $< -o $@
 
 #

diff --git a/bios/biosmem.c b/bios/biosmem.c
@@ -20,7 +20,7 @@
 #include "tosvars.h"
 
 
-extern MD themd;            /* BIOS memory descriptor (from tosvars.S) */
+extern MD themd;            /* BIOS memory descriptor */
 
 #if DBG_BALLOC
 static int bmem_allowed;

diff --git a/bios/tosvars.S b/bios/tosvars.S
@@ -7,232 +7,19 @@
  * option any later version.  See doc/license.txt for details.
  */
 
-#include "asmdefs.h"
-
-
-        .globl  bssstart
-        .globl  _proc_lives
-        .globl  _proc_dregs
-        .globl  _proc_aregs
-        .globl  _proc_enum
-        .globl  _proc_usp
-        .globl  _proc_stk
-
-        .globl  sysvars_start
-        .globl  _etv_timer
-        .globl  _etv_critic
-        .globl  _etv_term
-        .globl  _memvalid
-        .globl  memvalid
-        .globl  memctrl
-        .globl  resvalid
-        .globl  resvector
-        .globl  _phystop
-        .globl  _membot
-        .globl  _memtop
-        .globl  _memval2
-        .globl  memval2
-        .globl  _flock
-        .globl  _seekrate
-        .globl  _timer_ms
-        .globl  _fverify
-        .globl  _bootdev
-        .globl  _palmode
-        .globl  _defshiftmod
-        .globl  _sshiftmod
-        .globl  _v_bas_ad
-        .globl  _vblsem
-        .globl  _nvbls
-        .globl  _vblqueue
-        .globl  _colorptr
-        .globl  _screenpt
-        .globl  _vbclock
-        .globl  _frclock
-        .globl  _hdv_init
-        .globl  _swv_vec
-        .globl  _hdv_bpb
-        .globl  _hdv_rw
-        .globl  _hdv_boot
-        .globl  _hdv_mediach
-        .globl  _cmdload
-        .globl  _conterm
-        .globl  _themd
-        .globl  ____md
-        .globl  _savptr
-        .globl  _nflops
-        .globl  con_state
-        .globl  _save_row
-        .globl  sav_context
-        .globl  _bufl
-        .globl  _hz_200
-        .globl  the_env
-        .globl  _drvbits
-        .globl  _dskbufp
-        .globl  _autopath
-        .globl  _vbl_list
-        .globl  _dumpflg
-        .globl  _sysbase
-        .globl  _shell_p
-        .globl  _end_os
-        .globl  _exec_os
-        .globl  _dump_vec
-        .globl  _prt_stat
-        .globl  _prt_vec
-        .globl  _aux_stat
-        .globl  _aux_vec
-        .globl  _pun_ptr
-        .globl  _memval3
-        .globl  memval3
-        .globl  _bconstat_vec
-        .globl  _bconin_vec
-        .globl  _bcostat_vec
-        .globl  _bconout_vec
-#ifndef __mcoldfire__
-        .globl  _longframe
-#endif
-        .globl  _ramtop
-        .globl  _ramvalid
-        .globl  _bell_hook
-        .globl  _kcl_hook
-
-#if CONF_DETECT_FIRST_BOOT_WITHOUT_MEMCONF
-        .globl  _warm_magic
-#endif
-
-#ifdef CONF_WITH_68030_PMMU
-        .globl  _pmmutree
-#endif
-        .globl  sysvars_end
         .globl  _stkbot
         .globl  _stktop
+        .globl  bssstart
         .globl  _shifty
 
 // ===========================================================================
 // ==== BSS segment ==========================================================
 // ===========================================================================
 
-
-// ==== Beginning of RAM (used by OS) ========================================
         .bss
-        .org 0x00000000         // start of RAM
-
-// ==== Start of Exception related variables =================================
-        .org    0x380
-_proc_lives:    .ds.l   1       // validates system crash page, if 0x12345678
-_proc_dregs:    .ds.l   8       // saved registers d0-d7
-_proc_aregs:    .ds.l   8       // saved registers a0-a7
-_proc_enum:     .ds.l   1       // vector number of crash exception
-_proc_usp:      .ds.l   1       // saved user stackpointer
-_proc_stk:      .ds.w   16      // 16 words from exception stack
-
-// ==== Start of System variables ============================================
-        .org 0x400
-sysvars_start:
-_etv_timer:     .ds.l   1       // GEM event timer vector
-_etv_critic:    .ds.l   1       // GEM critical error handler
-_etv_term:      .ds.l   1       // GEM program termination vector
-_etv_xtra:      .ds.l   5       // GEM additional vectors (unused)
-_memvalid:
-memvalid:       .ds.l   1       // memory conf valid, if 0x752019f3
-        .org 0x424
-memctrl:        .ds.b   1       // copy of contents of 0xffff8001
-        .org 0x426
-resvalid:       .ds.l   1       // validates resvector, if 0x31415926
-resvector:      .ds.l   1       // reset vector
-_phystop:       .ds.l   1       // physical top of RAM
-_membot:        .ds.l   1       // start of TPA (user memory)
-_memtop:        .ds.l   1       // end of TPA (user memory)
-_memval2:
-memval2:        .ds.l   1       // validates memcntrl/memconf, if 0x237698aa
-_flock:         .ds.w   1       // if != 0, VBL floppy routine is disabled
-_seekrate:      .ds.w   1       // floppy seek rate
-_timer_ms:      .ds.w   1       // time between timer calls in ms
-_fverify:       .ds.w   1       // if != 0, verify floppy writes
-_bootdev:       .ds.w   1       // default boot drive
-_palmode:       .ds.w   1       // 0 = NTSC, else PAL
-_defshiftmod:   .ds.w   1       // default video resolution
-_sshiftmod:     .ds.b   1       // copy of contents of 0xffff8260
-        .org 0x44e
-_v_bas_ad:      .ds.l   1       // screen base address
-_vblsem:        .ds.w   1       // if > 0, the VBL routine is executed
-_nvbls:         .ds.w   1       // number of VBL routines
-_vblqueue:      .ds.l   1       // pointer to list of VBL routines
-_colorptr:      .ds.l   1       // pointer to color palette to be loaded
-_screenpt:      .ds.l   1       // pointer to video RAM for next VBL
-_vbclock:       .ds.l   1       // number of VBL routines executed
-_frclock:       .ds.l   1       // number of VBL routines processed
-_hdv_init:      .ds.l   1       // vector for hard disk initialization
-_swv_vec:       .ds.l   1       // vector for resolution change
-_hdv_bpb:       .ds.l   1       // vector for getbpb for harddisk
-_hdv_rw:        .ds.l   1       // vector for read/write for harddisk
-_hdv_boot:      .ds.l   1       // vector for hard disk boot
-_hdv_mediach:   .ds.l   1       // vector for hard disk media change
-_cmdload:       .ds.w   1       // if not 0, load command.prg after boot
-_conterm:       .ds.b   1       // attribute vector for console output
-trp14ret:       .ds.l   1       // return address for trap #14 (unused)
-criticret:      .ds.l   1       // return address for critical error hndlr
-        .org 0x48e
-_themd:         .ds.l   4       // first memory descriptor block
-____md:         .ds.w   2       // space for additional memory descriptors
-_savptr:        .ds.l   1       // pointer to BIOS save register block
-_nflops:        .ds.w   1       // number of connected floppy drives
-con_state:      .ds.l   1       // vector for screen output
-_save_row:      .ds.w   1       // temporary storage for cursor line pos.
-sav_context:    .ds.l   1       // ptr to save area for exception processing
-_bufl:          .ds.l   2       // pointers to buffer ctrl blocks for GEMDOS
-_hz_200:        .ds.l   1       // counter for 200 Hz system clock
-the_env:        .ds.l   1       // pointer to default environment string
-        .org 0x4c2
-_drvbits:       .ds.l   1       // bit allocation for physical drives
-_dskbufp:       .ds.l   1       // pointer to disk buffer
-_autopath:      .ds.l   1       // pointer to auto-execute path
-_vbl_list:      .ds.l   8       // pointers to 8 VBl routines
-_dumpflg:       .ds.w   1       // flag for screen dump (unsused)
-_prtabt:        .ds.w   1       // printer abort flag
-_sysbase:       .ds.l   1       // pointer to start of OS
-_shell_p:       .ds.l   1       // pointer to shell
-_end_os:        .ds.l   1       // pointer to end of OS
-_exec_os:       .ds.l   1       // pointer to entry point of OS
-
-        .org 0x502
-_dump_vec:      .ds.l   1       // pointer to screen dump routine
-_prt_stat:      .ds.l   1       // pointer to prv_lsto
-_prt_vec:       .ds.l   1       // pointer to prv_lst
-_aux_stat:      .ds.l   1       // pointer to prv_auxo
-_aux_vec:       .ds.l   1       // pointer to prv_aux
-_pun_ptr:       .ds.l   1       // if AHDI, pointer to pun_info
-_memval3:
-memval3:        .ds.l   1       // memory conf valid if = $5555aaaa
-_bconstat_vec:  .ds.l   8       // 8 pointers to input-status routines
-_bconin_vec:    .ds.l   8       // 8 pointers to input routines
-_bcostat_vec:   .ds.l   8       // 8 pointers to output-status routines
-_bconout_vec:   .ds.l   8       // 8 pointers to output routines
-_longframe:     .ds.w   1       // if not 0, then not 68000 - use long stack frames
-_p_cookies:     .ds.l   1       // pointer to cookie jar
-_ramtop:        .ds.l   1       // top of TT-RAM, or NULL if no TT-RAM is present
-_ramvalid:      .ds.l   1       // if equal to RAMVALID_MAGIC, then ramtop is valid
-_bell_hook:     .ds.l   1       // pointer to routine for system bell
-_kcl_hook:      .ds.l   1       // pointer to routine for system keyclick
-        .org 0x5b4
 
-#if CONF_DETECT_FIRST_BOOT_WITHOUT_MEMCONF
-        .org 0x6fc              // any location below bssstart is ok
-_warm_magic:    .ds.l   1       // set to WARM_MAGIC if next boot must not
-                                // be considered as a first boot (reset)
-#endif
-
-#if CONF_WITH_68030_PMMU
-        .org PMMUTREE_ADDRESS_68030
-_pmmutree:      .ds.l   64      // for pmmu tree on 68030
-#endif
-
-// Memory below 0x800 is only accessible in supervisor mode on the ST.
-// We have to make sure that nothing is linked into this region that might
-// be accessed from user mode, too.
-// (So the gap between 0x5b4 and 0x700 could be filled with system variables
-//  or a buffer that is only accessed in supervisor mode.)
-        .org 0x800
-sysvars_end:
+// This is the very beginning of the EmuTOS BSS segment.
+// It usually starts at 0x800, just after the system variables.
 
 // BIOS internal stack
 // Be sure to keep it under bssstart to avoid clearing it
@@ -250,5 +37,3 @@ bssstart:
 // assumes that it is half-word addressable, and may crash the system
 // otherwise.
 _shifty:        .ds.b   1       // reflects the status up/down of mode keys
-
-// The C global variables will be placed here
diff --git a/emutos.ld b/emutos.ld
@@ -17,6 +17,12 @@
 /* Create a plain binary ROM, without any header */
 OUTPUT_FORMAT(binary)
 
+/*
+ * The system variables have fixed addresses,
+ * they live in the 0x380-0x800 region.
+ */
+#include "tosvars.ld"
+
 SECTIONS
 {
   /* The TEXT segment is mapped at the beginning of the ROM.
@@ -43,11 +49,10 @@ SECTIONS
     __edata = .;
   }
 
-  /* The BSS segment starts at the beginning of the RAM.
-   * It includes the processor Exception Vector Table,
-   * system variables, and private variables.
+  /* By default, the BSS segment starts just after the system variables,
+   * at the bottom of the ST-RAM.
    */
-  .bss 0x00000000:
+  .bss sysvars_end :
   {
     *(.bss COMMON)
     __end = .;