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d54659b572
This patch adds more RAM optimizations to eLua:
- direct file memory mapping: files in ROMFS will be read directly from Flash,
without allocating any additional buffers. This doesn't help with RAM
consumption in itself, but enables the set of optimizations below.
- pseudo read-only strings. These are still TStrings, but the actual string
content can point directly to Flash. Original Lua strings are kept in
TStrings structures (lobject.h):
typedef union TString {
L_Umaxalign dummy; /* ensures maximum alignment for strings */
struct {
CommonHeader;
lu_byte reserved;
unsigned int hash;
size_t len;
} tsv;
} TString;
The actual string content comes right after the union TString above.
Pseudo RO strings have the same header, but instead of having the string
content after TString, they have a pointer that points to the actual
string content (which should exist in a RO memory (Flash) that is directly
accesbile from the MCU bus (like its internal Flash memory)). lua_newlstr
detects automatically if it should create a regular string or a pseudo RO
string by checking if the string pointer comes from the Flash region of the
MCU. This optimization works for both precompiled (.lc) files that exist in
ROMFS and for internal Lua strings (C code).
- functions in Flash: for precompiled (.lc) files that exist in ROMFS, the code
of the functions and a part of the debug information will be read directly
from Flash.
- ROMFS was changed to support files that are larger than 2**16 bytes and it
aligns all its files to an offset which is a multiple of 4 in order to prevent
data alignment issues with precompiled Lua code.
- the Lua bytecode dumper was changed to align all the instructions in a Lua
function and a part of the debug information to an offset which is a multiple
of 4. This might slightly increase the size of the precompiled Lua file.
These changes were succesfully checked against the Lua 5.1 test suite.
These changes were tested in eLua on LM3S and AVR32.
85 lines
2.7 KiB
C
85 lines
2.7 KiB
C
// Device manager interface for Newlib (stubs and additional IOCTL implementation)
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#ifndef __DEVMAN_H__
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#define __DEVMAN_H__
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#include "type.h"
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#include <reent.h>
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#include <unistd.h>
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// Maximum number of devices in the system
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#define DM_MAX_DEVICES 16
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#define DM_MAX_DEVICES_BITS 4
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// Maximum number of a device name
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#define DM_MAX_DEV_NAME 12
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// GLOBAL maximum file length (on ALL supported filesystem)
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#define DM_MAX_FNAME_LENGTH 30
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// Pack/unpack descriptions
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// Even if a file descriptor is an 'int', newlib treats it as a short, so we need to stuff
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// everything into 16 bits. Actually 15, since negative fd's are actually error indications
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#define DM_MAKE_DESC( devid, fd ) ( ( ( devid ) << ( 15 - DM_MAX_DEVICES_BITS ) ) | ( fd ) )
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#define DM_GET_DEVID( desc ) ( ( desc ) >> ( 15 - DM_MAX_DEVICES_BITS ) )
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#define DM_GET_FD( desc ) ( ( desc ) & ( ( 1 << ( 15 - DM_MAX_DEVICES_BITS ) ) - 1 ) )
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// STDIO file number
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#define DM_STDIN_NUM 0
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#define DM_STDOUT_NUM 1
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#define DM_STDERR_NUM 2
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// Our platform independent "dirent" structure (for opendir/readdir)
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struct dm_dirent {
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u32 fsize;
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const char *fname;
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u32 ftime;
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};
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typedef struct {
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u8 devid;
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void *userdata;
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} DM_DIR;
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// A device structure with pointers to all the device functions
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typedef struct
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{
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char name[ DM_MAX_DEV_NAME + 1 ];
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int ( *p_open_r )( struct _reent *r, const char *path, int flags, int mode );
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int ( *p_close_r )( struct _reent *r, int fd );
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_ssize_t ( *p_write_r ) ( struct _reent *r, int fd, const void *ptr, size_t len );
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_ssize_t ( *p_read_r )( struct _reent *r, int fd, void *ptr, size_t len );
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off_t ( *p_lseek_r )( struct _reent *r, int fd, off_t off, int whence );
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void* ( *p_opendir_r )( struct _reent *r, const char* name );
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struct dm_dirent* ( *p_readdir_r )( struct _reent *r, void *dir );
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int ( *p_closedir_r )( struct _reent *r, void* dir );
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const char* ( *p_getaddr_r )( struct _reent *r, int fd );
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} DM_DEVICE;
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// Errors
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#define DM_ERR_ALREADY_REGISTERED (-1)
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#define DM_ERR_NOT_REGISTERED (-2)
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#define DM_ERR_NO_SPACE (-3)
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#define DM_ERR_INVALID_NAME (-4)
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#define DM_ERR_NO_DEVICE (-5)
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#define DM_OK (0)
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// Add a device
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int dm_register( const DM_DEVICE *pdev );
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// Unregister a device
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int dm_unregister( const char* name );
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// Get a device entry
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const DM_DEVICE* dm_get_device_at( int idx );
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// Returns the number of registered devices
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int dm_get_num_devices();
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// Initialize device manager
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int dm_init();
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// DM specific functions (uniform over all the installed filesystems)
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DM_DIR *dm_opendir( const char* dirname );
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struct dm_dirent* dm_readdir( DM_DIR *d );
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int dm_closedir( DM_DIR *d );
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const char* dm_getaddr( int fd );
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#endif
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