/**
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/**
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* ion_noxram.lds -- Linker script file for ION project (with no RAM or cache)
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* ion_noxram.lds -- Linker script file for ION project (with no RAM or cache)
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*
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*
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* The ion cpu has separate buses for code and data (Harvard architecture) but
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* The ion cpu has separate buses for code and data (Harvard architecture) but
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* does not have caches by default. This linker script targets that 'bare'
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* does not have caches by default. This linker script targets that 'bare'
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* system configuration. It is meant for early testing and debugging.
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* system configuration. It is meant for early testing and debugging.
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*
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*
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* This script will split the object file in two areas so that they can be put
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* This script will split the object file in two areas so that they can be put
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* in separate memory blocks:
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* in separate memory blocks:
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* 1.- Code area (text output section)
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* 1.- Code area (text output section)
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* 2.- Data area (sdata, data and bss output sections)
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* 2.- Data area (sdata, data and bss output sections)
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*
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*
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* Since data constants can't be reached from the code bus, constant data
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* Since data constants can't be reached from the code bus, constant data
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* (usually in section rodata) needs to be put in the same space as other data.
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* (usually in section rodata) needs to be put in the same space as other data.
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* This is the main purpose of this file.
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* This is the main purpose of this file.
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* Alternatively, we might jus implement a 3-port memory and leave all sections
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* Alternatively, we might jus implement a 3-port memory and leave all sections
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* adjacent, but that would be too expensive (3-port memory would take about
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* adjacent, but that would be too expensive (3-port memory would take about
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* twice as many memory blocks for the same memory size).
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* twice as many memory blocks for the same memory size).
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*
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*
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* FIXME code and data RAM block sizes hardcoded
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* FIXME code and data RAM block sizes hardcoded
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* FIXME code and data start addresses hardcoded
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* FIXME code and data start addresses hardcoded
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*/
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*/
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/* Make sure the first linked file is ths startup code from boot.s */
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/* Make sure the first linked file is ths startup code from boot.s */
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/* (We might put boot.o in the ld command line, BEFORE all other files) */
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/* (We might put boot.o in the ld command line, BEFORE all other files) */
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STARTUP(boot.o)
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STARTUP(boot.o)
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/* Default object output format is ELF big endian */
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/* Default object output format is ELF big endian */
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OUTPUT_FORMAT(elf32-big)
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OUTPUT_FORMAT(elf32-big)
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SECTIONS {
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SECTIONS {
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/* Put all code at CODE area */
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/* Put all code at CODE area */
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.text 0x00000000 : {
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.text 0x00000000 : {
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_ftext = . ;
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_ftext = . ;
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* (.text);
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* (.text);
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} = 0 /* fill gaps with zeros */
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} = 0 /* fill gaps with zeros */
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/* Mark end of executable code */
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/* Mark end of executable code */
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_ecode = .;
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_ecode = .;
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/* mark end of read-only code */
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/* mark end of read-only code */
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_etext = .;
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_etext = .;
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PROVIDE (etext = .);
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PROVIDE (etext = .);
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/**** Put all data, including read-only, at DATA area */
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/**** Put all data, including read-only, at DATA area */
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.data 0x00010000 : {
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.data 0x80000000 : {
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_fdata = . ;
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_fdata = . ;
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* (.data);
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* (.data);
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* (.data.*);
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* (.data.*);
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/* Conventionally, symbol _gp points to the middle of a 64K area at the
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/* Conventionally, symbol _gp points to the middle of a 64K area at the
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start of the sdata section ('small data section'). Register $gp is
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start of the sdata section ('small data section'). Register $gp is
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loaded with _gp at program startup (in boot.s) so that data in that
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loaded with _gp at program startup (in boot.s) so that data in that
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area can be reached with just one instruction.
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area can be reached with just one instruction.
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Note that the compiler/assembler will put data in the sdata section
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Note that the compiler/assembler will put data in the sdata section
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only if it is small enough (see as/gcc docs, -G option and others).
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only if it is small enough (see as/gcc docs, -G option and others).
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FIXME this feature has not been tested.
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FIXME this feature has not been tested.
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*/
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*/
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_gp = . + 0x7ff0; /* 0x7ff0 -> middle of 64K area */
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_gp = . + 0x7ff0; /* 0x7ff0 -> middle of 64K area */
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*(.lit8);
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*(.lit8);
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*(.lit4);
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*(.lit4);
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*(.sdata);
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*(.sdata);
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*(.sbss);
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*(.sbss);
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*(.gnu.linkonce.s*);
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*(.gnu.linkonce.s*);
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*(.rodata);
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*(.rodata);
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*(.rodata.*);
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*(.rodata.*);
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/* mark end of initialised data */
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/* mark end of initialised data */
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_edata = .;
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_edata = .;
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PROVIDE (edata = .);
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PROVIDE (edata = .);
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/* start bss on dword boundary for easier clearing */
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/* start bss on dword boundary for easier clearing */
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. = ALIGN(8);
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. = ALIGN(8);
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}
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}
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/* start bss on dword boundary for easier clearing */
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/* start bss on dword boundary for easier clearing */
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. = ALIGN(8);
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. = ALIGN(8);
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/* mark start of uninitialised data */
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/* mark start of uninitialised data */
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__bss_start = .;
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__bss_start = .;
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_fbss = __bss_start;
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_fbss = __bss_start;
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.bss : {
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.bss : {
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/* *(.sbss); */
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/* *(.sbss); */
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*(.dynbss);
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*(.dynbss);
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*(COMMON);
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*(COMMON);
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* (.bss);
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* (.bss);
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_end = . ;
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_end = . ;
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}
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}
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/* mark end of uninitialised data */
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/* mark end of uninitialised data */
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_end = . ;
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_end = . ;
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PROVIDE (end = .);
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PROVIDE (end = .);
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}
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}
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