/* cpu_asm.s
*
* This file contains the basic algorithms for all assembly code used
* in an specific CPU port of RTEMS. These algorithms must be implemented
* in assembly language.
*
* COPYRIGHT (c) 1989-2011.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* Ported to ERC32 implementation of the SPARC by On-Line Applications
* Research Corporation (OAR) under contract to the European Space
* Agency (ESA).
*
* ERC32 modifications of respective RTEMS file: COPYRIGHT (c) 1995.
* European Space Agency.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/asm.h>
#include <rtems/system.h>
#if (SPARC_HAS_FPU == 1)
/*
* void _CPU_Context_save_fp(
* void **fp_context_ptr
* )
*
* This routine is responsible for saving the FP context
* at *fp_context_ptr. If the point to load the FP context
* from is changed then the pointer is modified by this routine.
*
* NOTE: See the README in this directory for information on the
* management of the "EF" bit in the PSR.
*/
.align 4
PUBLIC(_CPU_Context_save_fp)
SYM(_CPU_Context_save_fp):
save %sp, -CPU_MINIMUM_STACK_FRAME_SIZE, %sp
/*
* The following enables the floating point unit.
*/
mov %psr, %l0
sethi %hi(SPARC_PSR_EF_MASK), %l1
or %l1, %lo(SPARC_PSR_EF_MASK), %l1
or %l0, %l1, %l0
mov %l0, %psr ! **** ENABLE FLOAT ACCESS ****
nop; nop; nop; ! Need three nops before EF is
ld [%i0], %l0 ! active due to pipeline delay!!!
std %f0, [%l0 + FO_F1_OFFSET]
std %f2, [%l0 + F2_F3_OFFSET]
std %f4, [%l0 + F4_F5_OFFSET]
std %f6, [%l0 + F6_F7_OFFSET]
std %f8, [%l0 + F8_F9_OFFSET]
std %f10, [%l0 + F1O_F11_OFFSET]
std %f12, [%l0 + F12_F13_OFFSET]
std %f14, [%l0 + F14_F15_OFFSET]
std %f16, [%l0 + F16_F17_OFFSET]
std %f18, [%l0 + F18_F19_OFFSET]
std %f20, [%l0 + F2O_F21_OFFSET]
std %f22, [%l0 + F22_F23_OFFSET]
std %f24, [%l0 + F24_F25_OFFSET]
std %f26, [%l0 + F26_F27_OFFSET]
std %f28, [%l0 + F28_F29_OFFSET]
std %f30, [%l0 + F3O_F31_OFFSET]
st %fsr, [%l0 + FSR_OFFSET]
ret
restore
/*
* void _CPU_Context_restore_fp(
* void **fp_context_ptr
* )
*
* This routine is responsible for restoring the FP context
* at *fp_context_ptr. If the point to load the FP context
* from is changed then the pointer is modified by this routine.
*
* NOTE: See the README in this directory for information on the
* management of the "EF" bit in the PSR.
*/
.align 4
PUBLIC(_CPU_Context_restore_fp)
SYM(_CPU_Context_restore_fp):
save %sp, -CPU_MINIMUM_STACK_FRAME_SIZE , %sp
/*
* The following enables the floating point unit.
*/
mov %psr, %l0
sethi %hi(SPARC_PSR_EF_MASK), %l1
or %l1, %lo(SPARC_PSR_EF_MASK), %l1
or %l0, %l1, %l0
mov %l0, %psr ! **** ENABLE FLOAT ACCESS ****
nop; nop; nop; ! Need three nops before EF is
ld [%i0], %l0 ! active due to pipeline delay!!!
ldd [%l0 + FO_F1_OFFSET], %f0
ldd [%l0 + F2_F3_OFFSET], %f2
ldd [%l0 + F4_F5_OFFSET], %f4
ldd [%l0 + F6_F7_OFFSET], %f6
ldd [%l0 + F8_F9_OFFSET], %f8
ldd [%l0 + F1O_F11_OFFSET], %f10
ldd [%l0 + F12_F13_OFFSET], %f12
ldd [%l0 + F14_F15_OFFSET], %f14
ldd [%l0 + F16_F17_OFFSET], %f16
ldd [%l0 + F18_F19_OFFSET], %f18
ldd [%l0 + F2O_F21_OFFSET], %f20
ldd [%l0 + F22_F23_OFFSET], %f22
ldd [%l0 + F24_F25_OFFSET], %f24
ldd [%l0 + F26_F27_OFFSET], %f26
ldd [%l0 + F28_F29_OFFSET], %f28
ldd [%l0 + F3O_F31_OFFSET], %f30
ld [%l0 + FSR_OFFSET], %fsr
ret
restore
#endif /* SPARC_HAS_FPU */
/*
* void _CPU_Context_switch(
* Context_Control *run,
* Context_Control *heir
* )
*
* This routine performs a normal non-FP context switch.
*/
.align 4
PUBLIC(_CPU_Context_switch)
SYM(_CPU_Context_switch):
! skip g0
st %g1, [%o0 + G1_OFFSET] ! save the global registers
std %g2, [%o0 + G2_OFFSET]
std %g4, [%o0 + G4_OFFSET]
std %g6, [%o0 + G6_OFFSET]
! load the address of the ISR stack nesting prevention flag
sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %g2
ld [%g2 + %lo(SYM(_CPU_ISR_Dispatch_disable))], %g2
! save it a bit later so we do not waste a couple of cycles
std %l0, [%o0 + L0_OFFSET] ! save the local registers
std %l2, [%o0 + L2_OFFSET]
std %l4, [%o0 + L4_OFFSET]
std %l6, [%o0 + L6_OFFSET]
! Now actually save ISR stack nesting prevention flag
st %g2, [%o0 + ISR_DISPATCH_DISABLE_STACK_OFFSET]
std %i0, [%o0 + I0_OFFSET] ! save the input registers
std %i2, [%o0 + I2_OFFSET]
std %i4, [%o0 + I4_OFFSET]
std %i6, [%o0 + I6_FP_OFFSET]
std %o0, [%o0 + O0_OFFSET] ! save the output registers
std %o2, [%o0 + O2_OFFSET]
std %o4, [%o0 + O4_OFFSET]
std %o6, [%o0 + O6_SP_OFFSET]
rd %psr, %o2
st %o2, [%o0 + PSR_OFFSET] ! save status register
/*
* This is entered from _CPU_Context_restore with:
* o1 = context to restore
* o2 = psr
*/
PUBLIC(_CPU_Context_restore_heir)
SYM(_CPU_Context_restore_heir):
/*
* Flush all windows with valid contents except the current one.
* In examining the set register windows, one may logically divide
* the windows into sets (some of which may be empty) based on their
* current status:
*
* + current (i.e. in use),
* + used (i.e. a restore would not trap)
* + invalid (i.e. 1 in corresponding bit in WIM)
* + unused
*
* Either the used or unused set of windows may be empty.
*
* NOTE: We assume only one bit is set in the WIM at a time.
*
* Given a CWP of 5 and a WIM of 0x1, the registers are divided
* into sets as follows:
*
* + 0 - invalid
* + 1-4 - unused
* + 5 - current
* + 6-7 - used
*
* In this case, we only would save the used windows -- 6 and 7.
*
* Traps are disabled for the same logical period as in a
* flush all windows trap handler.
*
* Register Usage while saving the windows:
* g1 = current PSR
* g2 = current wim
* g3 = CWP
* g4 = wim scratch
* g5 = scratch
*/
ld [%o1 + PSR_OFFSET], %g1 ! g1 = saved psr
and %o2, SPARC_PSR_CWP_MASK, %g3 ! g3 = CWP
! g1 = psr w/o cwp
andn %g1, SPARC_PSR_ET_MASK | SPARC_PSR_CWP_MASK, %g1
or %g1, %g3, %g1 ! g1 = heirs psr
mov %g1, %psr ! restore status register and
! **** DISABLE TRAPS ****
mov %wim, %g2 ! g2 = wim
mov 1, %g4
sll %g4, %g3, %g4 ! g4 = WIM mask for CW invalid
save_frame_loop:
sll %g4, 1, %g5 ! rotate the "wim" left 1
srl %g4, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g4
or %g4, %g5, %g4 ! g4 = wim if we do one restore
/*
* If a restore would not underflow, then continue.
*/
andcc %g4, %g2, %g0 ! Any windows to flush?
bnz done_flushing ! No, then continue
nop
restore ! back one window
/*
* Now save the window just as if we overflowed to it.
*/
std %l0, [%sp + CPU_STACK_FRAME_L0_OFFSET]
std %l2, [%sp + CPU_STACK_FRAME_L2_OFFSET]
std %l4, [%sp + CPU_STACK_FRAME_L4_OFFSET]
std %l6, [%sp + CPU_STACK_FRAME_L6_OFFSET]
std %i0, [%sp + CPU_STACK_FRAME_I0_OFFSET]
std %i2, [%sp + CPU_STACK_FRAME_I2_OFFSET]
std %i4, [%sp + CPU_STACK_FRAME_I4_OFFSET]
std %i6, [%sp + CPU_STACK_FRAME_I6_FP_OFFSET]
ba save_frame_loop
nop
done_flushing:
add %g3, 1, %g3 ! calculate desired WIM
and %g3, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g3
mov 1, %g4
sll %g4, %g3, %g4 ! g4 = new WIM
mov %g4, %wim
or %g1, SPARC_PSR_ET_MASK, %g1
mov %g1, %psr ! **** ENABLE TRAPS ****
! and restore CWP
nop
nop
nop
! skip g0
ld [%o1 + G1_OFFSET], %g1 ! restore the global registers
ldd [%o1 + G2_OFFSET], %g2
ldd [%o1 + G4_OFFSET], %g4
ldd [%o1 + G6_OFFSET], %g6
! Load thread specific ISR dispatch prevention flag
ld [%o1 + ISR_DISPATCH_DISABLE_STACK_OFFSET], %o2
sethi %hi(SYM(_CPU_ISR_Dispatch_disable)), %o3
! Store it to memory later to use the cycles
ldd [%o1 + L0_OFFSET], %l0 ! restore the local registers
ldd [%o1 + L2_OFFSET], %l2
ldd [%o1 + L4_OFFSET], %l4
ldd [%o1 + L6_OFFSET], %l6
! Now restore thread specific ISR dispatch prevention flag
st %o2,[%o3 + %lo(SYM(_CPU_ISR_Dispatch_disable))]
ldd [%o1 + I0_OFFSET], %i0 ! restore the output registers
ldd [%o1 + I2_OFFSET], %i2
ldd [%o1 + I4_OFFSET], %i4
ldd [%o1 + I6_FP_OFFSET], %i6
ldd [%o1 + O2_OFFSET], %o2 ! restore the output registers
ldd [%o1 + O4_OFFSET], %o4
ldd [%o1 + O6_SP_OFFSET], %o6
! do o0/o1 last to avoid destroying heir context pointer
ldd [%o1 + O0_OFFSET], %o0 ! overwrite heir pointer
jmp %o7 + 8 ! return
nop ! delay slot
/*
* void _CPU_Context_restore(
* Context_Control *new_context
* )
*
* This routine is generally used only to perform restart self.
*
* NOTE: It is unnecessary to reload some registers.
*/
.align 4
PUBLIC(_CPU_Context_restore)
SYM(_CPU_Context_restore):
save %sp, -CPU_MINIMUM_STACK_FRAME_SIZE, %sp
rd %psr, %o2
ba SYM(_CPU_Context_restore_heir)
mov %i0, %o1 ! in the delay slot
.align 4
#if defined(RTEMS_SMP)
/*
* void _CPU_Context_switch_to_first_task_smp(
* Context_Control *new_context
* )
*
* This routine is only used to switch to the first task on a
* secondary core in an SMP configuration. We do not need to
* flush any windows and, in fact, this can be dangerous
* as they may or may not be initialized properly. So we just
* reinitialize the PSR and WIM.
*/
PUBLIC(_CPU_Context_switch_to_first_task_smp)
SYM(_CPU_Context_switch_to_first_task_smp):
mov %psr, %g1 ! Turn of traps when modifying WIM
andn %g1, SPARC_PSR_ET_MASK, %g1
mov %g1, %psr
/* WIM and PSR will be set in done_flushing, it need args:
* g1=PSR, g3=CWP, o1=Context
*/
and %g1, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g3
nop
mov %o0, %o1 ! in the delay slot
ba,a done_flushing
#endif
/* end of file */
