This file is part of SimpleRTOS2
; I found the following message in Microchip's support site. The URL is: ; http://support2.microchip.com/KBSearch/KB_Ticket.aspx?ID=Tt6UJ9A0003LM ; ; Unfortunately these pseudo-instructions don't work as inline assembly, ; so I had to make this separate .asm module. ; The functions are used inside 'port.c' and are called by 'pxPortInitialiseStack' ; (GetTMPDATALen, GetTMPDATAStrt, GetMATHDATALen, GetMATHDATAStrt) and ; by the macros 'portSAVE_CONTEXT' (SaveTMP_MATH) and 'portRESTORE_CONTEXT' ; (RestoreTMP_MATH'). ;------------------------------------------------------------------------------- ; Start of the message: ;------------------------------------------------------------------------------- ; ; Issue ; ; I'm developping a RTOS for the PIC18F258 using MPLAB-C18. I need to save in the ; task context the "MATH_DATA" and ".tmpdata" sections. But their address and size ; are only known after linking. The question is: How can I know the address and ; size of both sections at run time? ; ; Thanks ; ; Solution ; You CAN get the section location and size at runtime using MPASM. ; There are a few undocumented operators and pseudo-instructions. ; ; The SCNSZ operators give you the size of the section. ; The SCNSTART operators give you the starting address of a section. ; The SCNEND operators give you the ending address of a section. ; The SCNSTART_LFSR pseudo-instruction gives you an LFSR instruction with the starting address of the section. ; The SCNEND_LFSR pseudo-instruction gives you an LFSR instruction with the ending address of the section. ; ; Example: ; CODE ; movlw SCNSZ_LOW .tmpdata ; movlw SCNSZ_HIGH .tmpdata ; movlw SCNSZ_UPPER .tmpdata ; movlw SCNSTART_LOW .tmpdata ; movlw SCNSTART_HIGH .tmpdata ; movlw SCNSTART_UPPER .tmpdata ; movlw SCNEND_LOW .tmpdata ; movlw SCNEND_HIGH .tmpdata ; movlw SCNEND_UPPER .tmpdata ; ; SCNSTART_LFSR 0, .tmpdata ; SCNEND_LFSR 0, .tmpdata ; ; END ; ; These operators and pseudo-instructions will be documented in the next revision ; of the MPASM User's Guide. ; ;------------------------------------------------------------------------------- ; End of the message ;------------------------------------------------------------------------------- ;=============================================================================== ; Copyright (c) 2007-2008, Isaac Marino Bavaresco ; All rights reserved. ; ; Redistribution and use in source and binary forms, with or without ; modification, are permitted provided that the following conditions are met: ; * Redistributions of source code must retain the above copyright ; notice, this list of conditions and the following disclaimer. ; * Neither the name of the author nor the ; names of its contributors may be used to endorse or promote products ; derived from this software without specific prior written permission. ; ; THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY ; EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED ; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE ; DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY ; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ; (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ; ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS ; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ;=============================================================================== ; isaacbavaresco@yahoo.com.br ;=============================================================================== #include <P18CXXX.INC> ;=============================================================================== radix decimal ;=============================================================================== code ;=============================================================================== global GetTMPDATAStrt GetTMPDATAStrt: movlw SCNSTART_LOW .tmpdata movwf PRODL movlw SCNSTART_HIGH .tmpdata movwf PRODH return 0 ;=============================================================================== global GetTMPDATALen GetTMPDATALen: movlw SCNSZ_LOW .tmpdata return 0 ;=============================================================================== global GetMATHDATAStrt GetMATHDATAStrt:movlw SCNSTART_LOW MATH_DATA movwf PRODL movlw SCNSTART_HIGH MATH_DATA movwf PRODH return 0 ;=============================================================================== global GetMATHDATALen GetMATHDATALen: movlw SCNSZ_LOW MATH_DATA return 0 ;=============================================================================== global SaveTMP_MATH SaveTMP_MATH: SCNSTART_LFSR 0, .tmpdata movlw SCNSZ_LOW .tmpdata SaveLoop1: movff POSTINC0,PREINC1 addlw -1 bnz SaveLoop1 SCNSTART_LFSR 0, MATH_DATA movlw SCNSZ_LOW MATH_DATA SaveLoop2: movff POSTINC0,PREINC1 addlw -1 bnz SaveLoop2 return 0 ;=============================================================================== global RestoreTMP_MATH RestoreTMP_MATH: SCNEND_LFSR 0, MATH_DATA movlw SCNSZ_LOW MATH_DATA RestoreLoop1: movff POSTDEC1,POSTDEC0 addlw -1 bnz RestoreLoop1 SCNEND_LFSR 0, .tmpdata movlw SCNSZ_LOW .tmpdata RestoreLoop2: movff POSTDEC1,POSTDEC0 addlw -1 bnz RestoreLoop2 return 0 ;=============================================================================== end ;===============================================================================
file: /Techref/member/IMB-yahoo-J86/PortPIC18-ASM.asm.htm, 6KB, , updated: 2016/1/14 19:37, local time: 2024/11/12 17:06,
owner: IMB-yahoo-J86,
18.216.251.190:LOG IN
|
©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://ecomorder.com/techref/member/IMB-yahoo-J86/PortPIC18-ASM.asm.htm"> A simple RTOS for microcontrollers based upon concepts of FreeRTOS</A> |
Did you find what you needed? |