Mercurial > ecos-v2_0-branch
view packages/hal/powerpc/arch/current/src/context.S @ 12:4cc3eff958ab ecos-sw-1999-06-04
Merge from eCos master repository on 1999-06-04-22:24:56-BST
| author | jlarmour |
|---|---|
| date | Fri, 04 Jun 1999 15:08:16 +0000 |
| parents | 443894e2e912 |
| children | c38311975d4f |
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##============================================================================= ## ## context.S ## ## PowerPC context switch code ## ##============================================================================= #####COPYRIGHTBEGIN#### # # ------------------------------------------- # The contents of this file are subject to the Cygnus eCos Public License # Version 1.0 (the "License"); you may not use this file except in # compliance with the License. You may obtain a copy of the License at # http://sourceware.cygnus.com/ecos # # Software distributed under the License is distributed on an "AS IS" # basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the # License for the specific language governing rights and limitations under # the License. # # The Original Code is eCos - Embedded Cygnus Operating System, released # September 30, 1998. # # The Initial Developer of the Original Code is Cygnus. Portions created # by Cygnus are Copyright (C) 1998,1999 Cygnus Solutions. All Rights Reserved. # ------------------------------------------- # #####COPYRIGHTEND#### ##============================================================================= #######DESCRIPTIONBEGIN#### ## ## Author(s): nickg ## Contributors: nickg ## Date: 1998-04-27 ## Purpose: PowerPC context switch code ## Description: This file contains implementations of the thread context ## switch routines. It also contains the longjmp() and setjmp() ## routines. ## ######DESCRIPTIONEND#### ## ##============================================================================= #include <pkgconf/hal.h> #include "cyg/hal/ppc.inc" #------------------------------------------------------------------------------ # function declaration macro #define FUNC_START(name) \ .type name,@function; \ .globl name; \ name: #------------------------------------------------------------------------------ # Configure to use either a minimal or maximal thread state #ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM #define MIN_SAVE_REG 13 #define MAX_SAVE_REG 31 .macro save_special .endm .macro load_special .endm #else #define MIN_SAVE_REG 6 #define MAX_SAVE_REG 31 .macro save_special mfxer r6 mfctr r7 stw r6,ppcreg_xer(sp) stw r7,ppcreg_ctr(sp) .endm .macro load_special lwz r6,ppcreg_xer(sp) lwz r7,ppcreg_ctr(sp) mtxer r6 mtctr r7 .endm #endif #------------------------------------------------------------------------------ # hal_thread_switch_context # Switch thread contexts # R3 = address of sp of next thread to execute # R4 = address of sp save location of current thread FUNC_START(hal_thread_switch_context) mr r5,sp # R5 = saved stack pointer subi sp,sp,ppcreg_context_size # space for state # Save registers MIN..MAX .set _reg,MIN_SAVE_REG .rept MAX_SAVE_REG+1-MIN_SAVE_REG stw _reg,(ppcreg_regs+_reg*4)(sp) .set _reg,_reg+1 .endr stw r0,ppcreg_regs+0*4(sp) # R0 stw r5,ppcreg_regs+1*4(sp) # R5 = real SP, save in R1 slot stw r2,ppcreg_regs+2*4(sp) # R2 = TOC # CR cannot be treated as a special register since GCC will only # do partial restore of CR at function exit, depending on which # of CR2, CR3, and CR4 have been used in the given function. mfcr r5 # save CR. stw r5,ppcreg_cr(sp) #ifdef CYGDBG_HAL_DEBUG_GDB_THREAD_SUPPORT # Make the thread context look like an exception context if thread- # aware debugging is required. This state does not need restoring. mflr r5 stw r5,ppcreg_pc(sp) # pc of caller mfmsr r5 stw r5,ppcreg_msr(sp) # msr (or PS) #endif save_special # save special regs mflr r5 # save LR == return link for this fn stw r5,ppcreg_lr(sp) stw sp,0(r4) # save SP into save location # Now load the destination thread by dropping through # to hal_thread_load_context #------------------------------------------------------------------------------ # hal_thread_load_context # Load thread context # R3 = address of sp of next thread to execute # Note that this function is also the second half of hal_thread_switch_context # and is simply dropped into from it. FUNC_START(hal_thread_load_context) lwz sp,0(r3) # load state directly into SP load_special # load special registers lwz r5,ppcreg_cr(sp) # restore CR mtcr r5 lwz r5,ppcreg_lr(sp) # get LR as set as return link mtlr r5 # Load registers MIN..MAX .set _reg,MIN_SAVE_REG .rept MAX_SAVE_REG+1-MIN_SAVE_REG lwz _reg,(ppcreg_regs+_reg*4)(sp) .set _reg,_reg+1 .endr lwz r0,ppcreg_regs+0*4(sp) # R0 lwz r2,ppcreg_regs+2*4(sp) # R2 = TOC lwz r3,ppcreg_regs+3*4(sp) # load r3 lwz sp,ppcreg_regs+1*4(sp) # finally restore true SP blr # jump to LR #------------------------------------------------------------------------------ # HAL longjmp, setjmp implementations # hal_setjmp saves only to callee save registers 13-31, r1[sp],r2, cr[2-4] # and lr into buffer supplied in r3[arg0] # Note: These definitions are repeated in hal_arch.h. If changes are required # remember to update both sets. #define CYGARC_JMP_BUF_SP 0 #define CYGARC_JMP_BUF_R2 1 #define CYGARC_JMP_BUF_R13 2 #define CYGARC_JMP_BUF_R14 3 #define CYGARC_JMP_BUF_R15 4 #define CYGARC_JMP_BUF_R16 5 #define CYGARC_JMP_BUF_R17 6 #define CYGARC_JMP_BUF_R18 7 #define CYGARC_JMP_BUF_R19 8 #define CYGARC_JMP_BUF_R20 9 #define CYGARC_JMP_BUF_R21 10 #define CYGARC_JMP_BUF_R22 11 #define CYGARC_JMP_BUF_R23 12 #define CYGARC_JMP_BUF_R24 13 #define CYGARC_JMP_BUF_R25 14 #define CYGARC_JMP_BUF_R26 15 #define CYGARC_JMP_BUF_R27 16 #define CYGARC_JMP_BUF_R28 17 #define CYGARC_JMP_BUF_R29 18 #define CYGARC_JMP_BUF_R30 19 #define CYGARC_JMP_BUF_R31 20 #define CYGARC_JMP_BUF_LR 21 #define CYGARC_JMP_BUF_CR 22 #define CYGARC_JMP_BUF_SIZE 23 FUNC_START(hal_setjmp) mfcr r5 stw r5, CYGARC_JMP_BUF_CR*4(r3) mflr r5 stw r5, CYGARC_JMP_BUF_LR*4(r3) stw r31,CYGARC_JMP_BUF_R31*4(r3) stw r30,CYGARC_JMP_BUF_R30*4(r3) stw r29,CYGARC_JMP_BUF_R29*4(r3) stw r28,CYGARC_JMP_BUF_R28*4(r3) stw r27,CYGARC_JMP_BUF_R27*4(r3) stw r26,CYGARC_JMP_BUF_R26*4(r3) stw r25,CYGARC_JMP_BUF_R25*4(r3) stw r24,CYGARC_JMP_BUF_R24*4(r3) stw r23,CYGARC_JMP_BUF_R23*4(r3) stw r22,CYGARC_JMP_BUF_R22*4(r3) stw r21,CYGARC_JMP_BUF_R21*4(r3) stw r20,CYGARC_JMP_BUF_R20*4(r3) stw r19,CYGARC_JMP_BUF_R19*4(r3) stw r18,CYGARC_JMP_BUF_R18*4(r3) stw r17,CYGARC_JMP_BUF_R17*4(r3) stw r16,CYGARC_JMP_BUF_R16*4(r3) stw r15,CYGARC_JMP_BUF_R15*4(r3) stw r14,CYGARC_JMP_BUF_R14*4(r3) stw r13,CYGARC_JMP_BUF_R13*4(r3) stw r2, CYGARC_JMP_BUF_R2*4(r3) # TOC, optimize out? stw sp, CYGARC_JMP_BUF_SP*4(r3) li r3,0 # return 0 blr # hal_longjmp loads state from r3[arg0] and returns # and lr into buffer supplied in r3[arg0] FUNC_START(hal_longjmp) lwz r5,CYGARC_JMP_BUF_CR*4(r3) mtcr r5 lwz r5,CYGARC_JMP_BUF_LR*4(r3) mtlr r5 lwz r31,CYGARC_JMP_BUF_R31*4(r3) lwz r30,CYGARC_JMP_BUF_R30*4(r3) lwz r29,CYGARC_JMP_BUF_R29*4(r3) lwz r28,CYGARC_JMP_BUF_R28*4(r3) lwz r27,CYGARC_JMP_BUF_R27*4(r3) lwz r26,CYGARC_JMP_BUF_R26*4(r3) lwz r25,CYGARC_JMP_BUF_R25*4(r3) lwz r24,CYGARC_JMP_BUF_R24*4(r3) lwz r23,CYGARC_JMP_BUF_R23*4(r3) lwz r22,CYGARC_JMP_BUF_R22*4(r3) lwz r21,CYGARC_JMP_BUF_R21*4(r3) lwz r20,CYGARC_JMP_BUF_R20*4(r3) lwz r19,CYGARC_JMP_BUF_R19*4(r3) lwz r18,CYGARC_JMP_BUF_R18*4(r3) lwz r17,CYGARC_JMP_BUF_R17*4(r3) lwz r16,CYGARC_JMP_BUF_R16*4(r3) lwz r15,CYGARC_JMP_BUF_R15*4(r3) lwz r14,CYGARC_JMP_BUF_R14*4(r3) lwz r13,CYGARC_JMP_BUF_R13*4(r3) lwz r2, CYGARC_JMP_BUF_R2*4(r3) lwz sp, CYGARC_JMP_BUF_SP*4(r3) mr r3,r4 # return r4[arg1] blr #------------------------------------------------------------------------------ # end of context.S