/* Copyright (c) 2002, Marek Michalkiewicz 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. * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. * Neither the name of the copyright holders nor the names of contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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. */ /* $Id$ */ /* setjmp.S Contributors: Created by Marek Michalkiewicz <marekm@linux.org.pl> */ /* jmp_buf: offset size description 0 16/2 call-saved registers (r2-r17) (AVR_TINY arch has only 2 call saved registers (r18,r19)) 16/2 2 frame pointer (r29:r28) 18/4 2 stack pointer (SPH:SPL) 20/6 1 status register (SREG) 21/7 2/3 return address (PC) (2 bytes used for <=128Kw flash) 23/24/9 = total size (AVR_TINY arch always has 2 bytes PC) All multibytes are stored as little-endian. int setjmp(jmp_buf __jmpb); void longjmp(jmp_buf __jmpb, int __val) __attribute__((noreturn)); */ #ifndef __DOXYGEN__ #include <avr/io.h> #include "macros.inc" /* ???: What was a reason to use aliases for common registers? Check the address: is it a port number (value for IN/OUT)? */ #if AVR_STACK_POINTER_LO_ADDR != 0x3D \ || AVR_STATUS_ADDR != 0x3F # error "Strange address of common registers SPL, SREG" #endif #define jmpb_hi r25 #define jmpb_lo r24 #define val_hi r23 #define val_lo r22 #define ret_lo r24 #define ret_hi r25 ASSEMBLY_CLIB_SECTION .global _U(setjmp) .type _U(setjmp), @function _U(setjmp): X_movw XL, jmpb_lo ; save call-saved registers and frame pointer #if !defined(__AVR_TINY__) .irp .L_regno, 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,28,29 #else .irp .L_regno, 18,19,28,29 #endif st X+, r\.L_regno .endr ; get return address #if defined(__AVR_3_BYTE_PC__) && __AVR_3_BYTE_PC__ pop __tmp_reg__ ; used below #endif pop ZH pop ZL ; save stack pointer (after poping) in ret_lo, AVR_STACK_POINTER_LO_ADDR st X+, ret_lo #ifdef _HAVE_AVR_STACK_POINTER_HI in ret_lo, AVR_STACK_POINTER_HI_ADDR st X+, ret_lo #else st X+, __zero_reg__ #endif ; save status register (I flag) in ret_lo, AVR_STATUS_ADDR st X+, ret_lo ; save return address st X+, ZL st X+, ZH ; return zero clr ret_lo clr ret_hi #if defined(__AVR_3_BYTE_PC__) && __AVR_3_BYTE_PC__ st X+, __tmp_reg__ rjmp .L_jmp3 #else ijmp #endif .size _U(setjmp), . - _U(setjmp) .global _U(longjmp) .type _U(longjmp), @function _U(longjmp): X_movw XL, jmpb_lo ; return value X_movw ret_lo, val_lo ; if zero, change to 1 cpi ret_lo, 1 cpc ret_hi, __zero_reg__ adc ret_lo, __zero_reg__ ; restore call-saved registers and frame pointer #if !defined(__AVR_TINY__) .irp .L_regno, 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,28,29 #else .irp .L_regno, 18,19,28,29 #endif ld r\.L_regno, X+ .endr ; restore stack pointer (SP value before the setjmp() call) and SREG ld ZL, X+ ld ZH, X+ ld __tmp_reg__, X+ #if defined (__AVR_XMEGA__) && __AVR_XMEGA__ /* A write to SPL will automatically disable interrupts for up to 4 instructions or until the next I/O memory write. */ out AVR_STATUS_ADDR, __tmp_reg__ out AVR_STACK_POINTER_LO_ADDR, ZL out AVR_STACK_POINTER_HI_ADDR, ZH #else # ifdef _HAVE_AVR_STACK_POINTER_HI /* interrupts disabled for shortest possible time (3 cycles) */ cli out AVR_STACK_POINTER_HI_ADDR, ZH # endif /* Restore status register (including the interrupt enable flag). Interrupts are re-enabled only after the next instruction. */ out AVR_STATUS_ADDR, __tmp_reg__ out AVR_STACK_POINTER_LO_ADDR, ZL #endif ; get return address and jump ld ZL, X+ ld ZH, X+ #if defined(__AVR_3_BYTE_PC__) && __AVR_3_BYTE_PC__ ld __tmp_reg__, X+ .L_jmp3: push ZL push ZH push __tmp_reg__ ret #else ijmp #endif .size _U(longjmp), . - _U(longjmp) #endif /* !__DOXYGEN__ */