##============================================================================= ## ## context.S ## ## PowerPC context switch code ## ##============================================================================= #####COPYRIGHTBEGIN#### # # ------------------------------------------- # The contents of this file are subject to the Red Hat eCos Public License # Version 1.1 (the "License"); you may not use this file except in # compliance with the License. You may obtain a copy of the License at # http://www.redhat.com/ # # 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 Configurable Operating System, # released September 30, 1998. # # The Initial Developer of the Original Code is Red Hat. # Portions created by Red Hat are # Copyright (C) 1998, 1999, 2000 Red Hat, Inc. # 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 #include #include #------------------------------------------------------------------------------ # 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,CYGARC_PPCREG_XER(sp) stw r7,CYGARC_PPCREG_CTR(sp) .endm .macro load_special lwz r6,CYGARC_PPCREG_XER(sp) lwz r7,CYGARC_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,CYGARC_PPC_CONTEXT_SIZE # space for state # Save registers MIN..MAX .set _reg,MIN_SAVE_REG .rept MAX_SAVE_REG+1-MIN_SAVE_REG stw _reg,(CYGARC_PPCREG_REGS+_reg*4)(sp) .set _reg,_reg+1 .endr stw r0,CYGARC_PPCREG_REGS+0*4(sp) # R0 stw r5,CYGARC_PPCREG_REGS+1*4(sp) # R5 = real SP, save in R1 slot stw r2,CYGARC_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,CYGARC_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,CYGARC_PPCREG_PC(sp) # pc of caller #endif mfmsr r5 stw r5,CYGARC_PPCREG_MSR(sp)# msr (or PS) save_special # save special regs mflr r5 # save LR == return link for this fn stw r5,CYGARC_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,CYGARC_PPCREG_CR(sp) # restore CR mtcr r5 lwz r5,CYGARC_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,(CYGARC_PPCREG_REGS+_reg*4)(sp) .set _reg,_reg+1 .endr lwz r3,CYGARC_PPCREG_MSR(sp) # merge interrupt state hal_cpu_int_merge r3 lwz r0,CYGARC_PPCREG_REGS+0*4(sp) # R0 lwz r2,CYGARC_PPCREG_REGS+2*4(sp) # R2 = TOC lwz r3,CYGARC_PPCREG_REGS+3*4(sp) # load r3 lwz sp,CYGARC_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] FUNC_START(hal_setjmp) mfcr r5 stw r5, CYGARC_JMPBUF_CR(r3) mflr r5 stw r5, CYGARC_JMPBUF_LR(r3) stw r31,CYGARC_JMPBUF_R31(r3) stw r30,CYGARC_JMPBUF_R30(r3) stw r29,CYGARC_JMPBUF_R29(r3) stw r28,CYGARC_JMPBUF_R28(r3) stw r27,CYGARC_JMPBUF_R27(r3) stw r26,CYGARC_JMPBUF_R26(r3) stw r25,CYGARC_JMPBUF_R25(r3) stw r24,CYGARC_JMPBUF_R24(r3) stw r23,CYGARC_JMPBUF_R23(r3) stw r22,CYGARC_JMPBUF_R22(r3) stw r21,CYGARC_JMPBUF_R21(r3) stw r20,CYGARC_JMPBUF_R20(r3) stw r19,CYGARC_JMPBUF_R19(r3) stw r18,CYGARC_JMPBUF_R18(r3) stw r17,CYGARC_JMPBUF_R17(r3) stw r16,CYGARC_JMPBUF_R16(r3) stw r15,CYGARC_JMPBUF_R15(r3) stw r14,CYGARC_JMPBUF_R14(r3) stw r13,CYGARC_JMPBUF_R13(r3) stw r2, CYGARC_JMPBUF_R2(r3) # TOC, optimize out? stw sp, CYGARC_JMPBUF_SP(r3) li r3,0 # return 0 blr # hal_longjmp loads state from r3[arg0] and returns # to the setjmp caller with r4[arg1] as return value FUNC_START(hal_longjmp) lwz r5,CYGARC_JMPBUF_CR(r3) mtcr r5 lwz r5,CYGARC_JMPBUF_LR(r3) mtlr r5 lwz r31,CYGARC_JMPBUF_R31(r3) lwz r30,CYGARC_JMPBUF_R30(r3) lwz r29,CYGARC_JMPBUF_R29(r3) lwz r28,CYGARC_JMPBUF_R28(r3) lwz r27,CYGARC_JMPBUF_R27(r3) lwz r26,CYGARC_JMPBUF_R26(r3) lwz r25,CYGARC_JMPBUF_R25(r3) lwz r24,CYGARC_JMPBUF_R24(r3) lwz r23,CYGARC_JMPBUF_R23(r3) lwz r22,CYGARC_JMPBUF_R22(r3) lwz r21,CYGARC_JMPBUF_R21(r3) lwz r20,CYGARC_JMPBUF_R20(r3) lwz r19,CYGARC_JMPBUF_R19(r3) lwz r18,CYGARC_JMPBUF_R18(r3) lwz r17,CYGARC_JMPBUF_R17(r3) lwz r16,CYGARC_JMPBUF_R16(r3) lwz r15,CYGARC_JMPBUF_R15(r3) lwz r14,CYGARC_JMPBUF_R14(r3) lwz r13,CYGARC_JMPBUF_R13(r3) lwz r2, CYGARC_JMPBUF_R2(r3) lwz sp, CYGARC_JMPBUF_SP(r3) mr r3,r4 # return r4[arg1] blr #------------------------------------------------------------------------------ # end of context.S