| Purpose: |
Copy an ASCIIz string from FLASH to an SRAM buffer.
The
source string in FLASH can be a zero length string, in which case only
a single BYTE is copied.
The system function
strlenPGM is used to determine the string length, then limited to
254 BYTEs. |
| Assumes: |
szPtrToSRAM and szPtrFromFLASH contain valid addresses.
The string to copy from FLASH is less than 255 characters in length.
The string ends in 0x00, 0xFE, or 0xFF BYTE values.
Any other BYTE
value (1 to 253 = 0xFD) is considered to be part of the string. |
|
There destination buffer has room for the string, which
cannot exceed 255 bytes. |
| Passed: |
R25:R24 |
CHAR * |
szPtrToSRAM |
the SRAM destination address |
|
R23:R22 |
CHAR * |
szPtrFromFLASH |
the 328P FLASH source address OR |
|
R26:R23:R22 |
CHAR * |
szPtrFromFLASH |
the 1284P or 2560 FLASH source address |
| Returns: |
R25:R24 |
CHAR * |
szPtrTo |
the caller's szPtrToSRAM value (unmodified) |
| Alters: |
R22, R23, R26, R27, R30, R31, the FLAGs and the SRAM buffer |
| Example: |
.ORG 0x1000
CopyFromFLASH:
ADIW R26, 0 ; If 'X' is zero, the command line has nothing
BREQ ACopyFromFLASH_Ret ; to be checked, so just exit immediately
MOVW R24, R26 ; Transfer the buffer pointer to R25:R24 and
LDI R22, ' ' ; set the search character in R22, then try
CALL AParseValueAfter ; to parse a value after the first space
SBRS R21, BIT_PV_VALID ; Exit if the parser says "nothing there"
CopyFromFLASH_Ret:
RET
MOVW R30, R22 ; The first value parsed is the SRAM address
MOVW R24, R26 ; Point to the BYTE after the parsed string
CALL AParseValue ; to parse a value after the first space
SBRS R21, BIT_PV_VALID
RET ; If valid, R23:R22 has the FLASH data source
MOVW R24, R30 ; Set the destination SRAM address from 'Z'
JMP AstrcpyPGM ; Copy the string from FLASH to SRAM and exit
|
| Test it: |
>DS+ 0x600 80
SRAM contents:
0600: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0610: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0620: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0630: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0640: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
>DP+ 0x3F70 80
FLASH (program memory) contents:
3F70: 20 50 72 6F 20 4D 69 6E-69 0D 0A 56 65 72 73 69 Pro Mini..Versi
3F80: 6F 6E 20 33 2E 30 31 20-2D 20 4D 6F 6E 64 61 79 on 3.01 - Monday
3F90: 2C 20 4D 61 72 63 68 20-32 38 2C 20 32 30 32 32 , March 28, 2022
3FA0: 0D 0A 00 00 00 00 00 00-00 00 00 00 00 00 CA 9A ................
3FB0: 3B 00 E1 F5 05 80 96 98-00 40 42 0F 00 A0 86 01 ;........@B.....
> ; Login to use the indirect subroutine call (the '@' command)
m>EIF 0x610 0x3F7B 40 ; Syntax: edit, SRAM dest, FLASH memory source, count
m>DS+ 0x600 80
SRAM contents:
0600: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
0610: 56 65 72 73 69 6F 6E 20-33 2E 30 31 20 2D 20 4D Version 3.01 - M
0620: 6F 6E 64 61 79 2C 20 4D-61 72 63 68 20 32 38 2C onday, March 28,
0630: 20 32 30 32 32 0D 0A 00-00 00 00 00 00 00 00 00 2022...........
0640: 00 00 00 00 00 00 00 00-00 00 00 00 00 00 00 00 ................
m>
|
| Notes: |
An ASCIIz string is a series of printable characters,
terminated with a NULL (= 0) BYTE. |
| The szPtrToSRAM and szPtrFromFLASH values are not checked for validity. |
Dropin:
(setup
code) |
; Setup for the strcpyPGM() or strcpyFLASH() call:
; Passed: R25:R24 CHAR * szPtrToSRAM pointer to the SRAM buffer
; R23:R22 CHAR * szPtrFromFLASH pointer to the 328P FLASH source string OR
; R26:R23:R22 CHAR * szPtrFromFLASH pointer to string in 1284P or 2560 FLASH
; Returns: R25:R24 CHAR * the caller's szPtrTo value (unmodified)
; Assumes: The desination SRAM buffer has room for the string
; Alters: R22, R23, R26, R27, R30, R31, the FLAGs and the SRAM buffer |
| Also see: |
The memcpyPGM,
strcmpPGM,
strlenPGM,
memcpy,
strcpy,
strlen,
and memcpyEEPROM System Functions as well as
the EIF (in Edit) System Command. |