| 1 |
786 |
skrzyp |
/*=============================================================================
|
| 2 |
|
|
//
|
| 3 |
|
|
// context.S
|
| 4 |
|
|
//
|
| 5 |
|
|
// SPARClite context switch code
|
| 6 |
|
|
//
|
| 7 |
|
|
//=============================================================================
|
| 8 |
|
|
// ####ECOSGPLCOPYRIGHTBEGIN####
|
| 9 |
|
|
// -------------------------------------------
|
| 10 |
|
|
// This file is part of eCos, the Embedded Configurable Operating System.
|
| 11 |
|
|
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
|
| 12 |
|
|
//
|
| 13 |
|
|
// eCos is free software; you can redistribute it and/or modify it under
|
| 14 |
|
|
// the terms of the GNU General Public License as published by the Free
|
| 15 |
|
|
// Software Foundation; either version 2 or (at your option) any later
|
| 16 |
|
|
// version.
|
| 17 |
|
|
//
|
| 18 |
|
|
// eCos is distributed in the hope that it will be useful, but WITHOUT
|
| 19 |
|
|
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
| 20 |
|
|
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
| 21 |
|
|
// for more details.
|
| 22 |
|
|
//
|
| 23 |
|
|
// You should have received a copy of the GNU General Public License
|
| 24 |
|
|
// along with eCos; if not, write to the Free Software Foundation, Inc.,
|
| 25 |
|
|
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
|
| 26 |
|
|
//
|
| 27 |
|
|
// As a special exception, if other files instantiate templates or use
|
| 28 |
|
|
// macros or inline functions from this file, or you compile this file
|
| 29 |
|
|
// and link it with other works to produce a work based on this file,
|
| 30 |
|
|
// this file does not by itself cause the resulting work to be covered by
|
| 31 |
|
|
// the GNU General Public License. However the source code for this file
|
| 32 |
|
|
// must still be made available in accordance with section (3) of the GNU
|
| 33 |
|
|
// General Public License v2.
|
| 34 |
|
|
//
|
| 35 |
|
|
// This exception does not invalidate any other reasons why a work based
|
| 36 |
|
|
// on this file might be covered by the GNU General Public License.
|
| 37 |
|
|
// -------------------------------------------
|
| 38 |
|
|
// ####ECOSGPLCOPYRIGHTEND####
|
| 39 |
|
|
//=============================================================================
|
| 40 |
|
|
//#####DESCRIPTIONBEGIN####
|
| 41 |
|
|
//
|
| 42 |
|
|
// Author(s): nickg, gthomas, hmt
|
| 43 |
|
|
// Contributors: nickg, gthomas, hmt
|
| 44 |
|
|
// Date: 1998-12-15
|
| 45 |
|
|
// Purpose: SPARClite context switch code
|
| 46 |
|
|
// Description: This file contains implementations of the thread context
|
| 47 |
|
|
// switch routines. It also contains the longjmp() and setjmp()
|
| 48 |
|
|
// routines.
|
| 49 |
|
|
//
|
| 50 |
|
|
//####DESCRIPTIONEND####
|
| 51 |
|
|
//
|
| 52 |
|
|
//===========================================================================*/
|
| 53 |
|
|
|
| 54 |
|
|
#include
|
| 55 |
|
|
|
| 56 |
|
|
#include
|
| 57 |
|
|
|
| 58 |
|
|
#define DELAYS_AFTER_WRPSR_SAME_WINDOW
|
| 59 |
|
|
#define DELAYS_AFTER_WRWIM
|
| 60 |
|
|
|
| 61 |
|
|
.text
|
| 62 |
|
|
|
| 63 |
|
|
! ------------------------------------------------------------------------------
|
| 64 |
|
|
! hal_thread_switch_context
|
| 65 |
|
|
! Switch thread contexts
|
| 66 |
|
|
! %o0 = address of sp of next thread to execute
|
| 67 |
|
|
! %o1 = address of sp save location of current thread
|
| 68 |
|
|
|
| 69 |
|
|
.global hal_thread_switch_context
|
| 70 |
|
|
hal_thread_switch_context:
|
| 71 |
|
|
|
| 72 |
|
|
! First take the stack down to make room for the saved register
|
| 73 |
|
|
! state, including a window save area at the base. Leave the
|
| 74 |
|
|
! current window save area undisturbed. It is unused within the
|
| 75 |
|
|
! save but will become current again when we continue in this
|
| 76 |
|
|
! context. This lets us do this whole piece of work without
|
| 77 |
|
|
! diabling interrupts for too long, since, for example, we can
|
| 78 |
|
|
! lower the stack atomically with one instruction:
|
| 79 |
|
|
sub %sp, SAVE_REGS_SIZE, %sp
|
| 80 |
|
|
st %sp, [ %o1 ] ! return SP for this thread
|
| 81 |
|
|
|
| 82 |
|
|
std %l0, [%sp + 0 * 4] ! save L & I registers
|
| 83 |
|
|
std %l2, [%sp + 2 * 4]
|
| 84 |
|
|
std %l4, [%sp + 4 * 4]
|
| 85 |
|
|
std %l6, [%sp + 6 * 4]
|
| 86 |
|
|
|
| 87 |
|
|
std %i0, [%sp + 8 * 4]
|
| 88 |
|
|
std %i2, [%sp + 10 * 4]
|
| 89 |
|
|
std %i4, [%sp + 12 * 4]
|
| 90 |
|
|
std %i6, [%sp + 14 * 4]
|
| 91 |
|
|
|
| 92 |
|
|
#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 93 |
|
|
st %o7, [%sp + 31 * 4] ! save only the return address
|
| 94 |
|
|
! and no need to preserve %o0 even though it is restored
|
| 95 |
|
|
#else // save a maximal context
|
| 96 |
|
|
st %g1, [%sp + 17 * 4] ! save G & O registers
|
| 97 |
|
|
std %g2, [%sp + 18 * 4]
|
| 98 |
|
|
std %g4, [%sp + 20 * 4]
|
| 99 |
|
|
std %g6, [%sp + 22 * 4]
|
| 100 |
|
|
|
| 101 |
|
|
std %o0, [%sp + 24 * 4]
|
| 102 |
|
|
std %o2, [%sp + 26 * 4]
|
| 103 |
|
|
std %o4, [%sp + 28 * 4]
|
| 104 |
|
|
std %o6, [%sp + 30 * 4]
|
| 105 |
|
|
#endif // !CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 106 |
|
|
! and save the CWP in %g0 save place
|
| 107 |
|
|
rd %psr, %g7
|
| 108 |
|
|
st %g7, [%sp + 16 * 4]
|
| 109 |
|
|
|
| 110 |
|
|
! Now load the destination thread by dropping through
|
| 111 |
|
|
! to hal_thread_load_context
|
| 112 |
|
|
|
| 113 |
|
|
! ------------------------------------------------------------------------------
|
| 114 |
|
|
! hal_thread_load_context
|
| 115 |
|
|
! Load thread context
|
| 116 |
|
|
! %o0 = address of sp of next thread to execute
|
| 117 |
|
|
! Note that this function is also the second half of hal_thread_switch_context
|
| 118 |
|
|
! and is simply dropped into from it.
|
| 119 |
|
|
|
| 120 |
|
|
.global hal_thread_load_context
|
| 121 |
|
|
hal_thread_load_context:
|
| 122 |
|
|
|
| 123 |
|
|
! Here, we are a leaf routine but with slightly odd properties.
|
| 124 |
|
|
! The stack is still the callers at this point but the register
|
| 125 |
|
|
! set is up for grabs. So we can use globals:
|
| 126 |
|
|
|
| 127 |
|
|
ld [ %o0 ], %g7 ! Get the next saved SP
|
| 128 |
|
|
|
| 129 |
|
|
! DISABLE INTERRUPTS *ONLY* NOT TRAPS
|
| 130 |
|
|
rd %psr, %g6
|
| 131 |
|
|
or %g6, 0xfe0, %g5 ! PIL up to 15 leave traps enabled
|
| 132 |
|
|
wr %g5, %psr
|
| 133 |
|
|
|
| 134 |
|
|
! force out all our callers register sets onto the stack
|
| 135 |
|
|
! if necessary: the system will handily take care of this for
|
| 136 |
|
|
! us as follows:
|
| 137 |
|
|
save %sp, -16 * 4, %sp ! need all these to preserve
|
| 138 |
|
|
save %sp, -16 * 4, %sp ! the linked list property...
|
| 139 |
|
|
save %sp, -16 * 4, %sp
|
| 140 |
|
|
save %sp, -16 * 4, %sp
|
| 141 |
|
|
#if 6 < __WINSIZE
|
| 142 |
|
|
save %sp, -16 * 4, %sp
|
| 143 |
|
|
#if 7 < __WINSIZE
|
| 144 |
|
|
save %sp, -16 * 4, %sp
|
| 145 |
|
|
#endif
|
| 146 |
|
|
#endif
|
| 147 |
|
|
! Fewer saves if fewer register windows. For 8 register windows,
|
| 148 |
|
|
! six of these is correct; a seventh would force out the current
|
| 149 |
|
|
! set that was already saved manually above. Note that minimal
|
| 150 |
|
|
! space is allowed on stack for locals and ins in case this
|
| 151 |
|
|
! sequence itself gets interrupted and recurses too deep.
|
| 152 |
|
|
|
| 153 |
|
|
! now select the new window with traps disabled...
|
| 154 |
|
|
|
| 155 |
|
|
! get the new PSR and CWP that we will ultimately restore
|
| 156 |
|
|
! from the %g0 save place...
|
| 157 |
|
|
ld [%g7 + 16 * 4], %g6 ! %g7 holds the new stack pointer
|
| 158 |
|
|
andn %g6, 0x20, %g5 ! clear ET into %g5
|
| 159 |
|
|
and %g6, __WINBITS, %g4 ! CWP bits only in %g4
|
| 160 |
|
|
|
| 161 |
|
|
! calculate a new WIM...
|
| 162 |
|
|
add %g4, 1, %g3 ! required invalid window number
|
| 163 |
|
|
#if 8 == __WINSIZE
|
| 164 |
|
|
and %g3, __WINBITS, %g3 ! modulo 8
|
| 165 |
|
|
#else // expect 5 or 6 or 7 windows
|
| 166 |
|
|
cmp %g3, __WINSIZE
|
| 167 |
|
|
bge,a 567f ! taken: do delay slot, handle overflow
|
| 168 |
|
|
mov 0, %g3 ! only if .ge. above
|
| 169 |
|
|
567:
|
| 170 |
|
|
#endif
|
| 171 |
|
|
mov 1, %g2
|
| 172 |
|
|
sll %g2, %g3, %g2 ! converted to a mask for the WIM
|
| 173 |
|
|
|
| 174 |
|
|
! DISABLE INTERRUPTS (TRAPS)
|
| 175 |
|
|
wr %g5, %psr ! set CWP to new window, disable traps
|
| 176 |
|
|
wr %g2, %wim ! and WIM to new value
|
| 177 |
|
|
nop
|
| 178 |
|
|
nop
|
| 179 |
|
|
nop
|
| 180 |
|
|
|
| 181 |
|
|
! Must do this atomically so that the registers match the stack.
|
| 182 |
|
|
! After locals and ins are loaded, we are conformant to the PCS
|
| 183 |
|
|
! so can re-enable interrupts.
|
| 184 |
|
|
mov %g7, %sp ! target sp in situ (%sp = %o6)
|
| 185 |
|
|
|
| 186 |
|
|
ldd [%sp + 0 * 4], %l0 ! restore L & I registers
|
| 187 |
|
|
ldd [%sp + 2 * 4], %l2
|
| 188 |
|
|
ldd [%sp + 4 * 4], %l4
|
| 189 |
|
|
ldd [%sp + 6 * 4], %l6
|
| 190 |
|
|
|
| 191 |
|
|
ldd [%sp + 8 * 4], %i0
|
| 192 |
|
|
ldd [%sp + 10 * 4], %i2
|
| 193 |
|
|
ldd [%sp + 12 * 4], %i4
|
| 194 |
|
|
ldd [%sp + 14 * 4], %i6
|
| 195 |
|
|
|
| 196 |
|
|
! RESTORE INTERRUPTS to saved state
|
| 197 |
|
|
wr %g6, %psr ! set new CWP and old ET and PIL
|
| 198 |
|
|
nop
|
| 199 |
|
|
nop
|
| 200 |
|
|
nop
|
| 201 |
|
|
|
| 202 |
|
|
! now load the rest of the context; we can be interrupted here
|
| 203 |
|
|
! (if the saved context was a voluntary yield or threadstart)
|
| 204 |
|
|
! but that is OK, other state will be preserved in that case...
|
| 205 |
|
|
|
| 206 |
|
|
#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 207 |
|
|
ld [%sp + 24 * 4], %o0 ! must load the initial argument
|
| 208 |
|
|
#else // restore a maximal context
|
| 209 |
|
|
ld [%sp + 17 * 4], %g1
|
| 210 |
|
|
ldd [%sp + 18 * 4], %g2
|
| 211 |
|
|
ldd [%sp + 20 * 4], %g4
|
| 212 |
|
|
ldd [%sp + 22 * 4], %g6
|
| 213 |
|
|
|
| 214 |
|
|
ldd [%sp + 24 * 4], %o0
|
| 215 |
|
|
ldd [%sp + 26 * 4], %o2
|
| 216 |
|
|
ldd [%sp + 28 * 4], %o4
|
| 217 |
|
|
#endif // !CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 218 |
|
|
! %o6 = %sp, already set up
|
| 219 |
|
|
ld [%sp + 31 * 4], %o7 ! "return" address
|
| 220 |
|
|
|
| 221 |
|
|
retl
|
| 222 |
|
|
add %sp, SAVE_REGS_SIZE, %sp ! and set the stack back
|
| 223 |
|
|
! to its entrant value
|
| 224 |
|
|
|
| 225 |
|
|
! ------------------------------------------------------------------------------
|
| 226 |
|
|
! HAL longjmp, setjmp implementations
|
| 227 |
|
|
|
| 228 |
|
|
!FUNC_START(hal_setjmp)
|
| 229 |
|
|
.global hal_setjmp
|
| 230 |
|
|
hal_setjmp:
|
| 231 |
|
|
! Treat this as a leaf routine, may as well.
|
| 232 |
|
|
! %o0 is the address of the buffer.
|
| 233 |
|
|
|
| 234 |
|
|
std %l0, [%o0 + 0 * 4] ! save L & I registers
|
| 235 |
|
|
std %l2, [%o0 + 2 * 4]
|
| 236 |
|
|
std %l4, [%o0 + 4 * 4]
|
| 237 |
|
|
std %l6, [%o0 + 6 * 4]
|
| 238 |
|
|
|
| 239 |
|
|
std %i0, [%o0 + 8 * 4]
|
| 240 |
|
|
std %i2, [%o0 + 10 * 4]
|
| 241 |
|
|
std %i4, [%o0 + 12 * 4]
|
| 242 |
|
|
std %i6, [%o0 + 14 * 4]
|
| 243 |
|
|
|
| 244 |
|
|
#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 245 |
|
|
std %o6, [%o0 + 30 * 4] ! just save %sp and return address
|
| 246 |
|
|
#else // save a maximal context
|
| 247 |
|
|
st %g1, [%o0 + 17 * 4] ! save G & O registers
|
| 248 |
|
|
std %g2, [%o0 + 18 * 4]
|
| 249 |
|
|
std %g4, [%o0 + 20 * 4]
|
| 250 |
|
|
std %g6, [%o0 + 22 * 4]
|
| 251 |
|
|
|
| 252 |
|
|
std %o0, [%o0 + 24 * 4]
|
| 253 |
|
|
std %o2, [%o0 + 26 * 4]
|
| 254 |
|
|
std %o4, [%o0 + 28 * 4]
|
| 255 |
|
|
std %o6, [%o0 + 30 * 4]
|
| 256 |
|
|
#endif // !CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 257 |
|
|
|
| 258 |
|
|
! and save the CWP in %g0 save place
|
| 259 |
|
|
rd %psr, %g7
|
| 260 |
|
|
st %g7, [%o0 + 16 * 4]
|
| 261 |
|
|
|
| 262 |
|
|
! DISABLE INTERRUPTS *ONLY* NOT TRAPS
|
| 263 |
|
|
or %g7, 0xfe0, %g6 ! PIL up to 15 leave traps enabled
|
| 264 |
|
|
wr %g6, %psr
|
| 265 |
|
|
|
| 266 |
|
|
! force out all our callers register sets onto the stack
|
| 267 |
|
|
! if necessary: the system will handily take care of this for
|
| 268 |
|
|
! us as follows:
|
| 269 |
|
|
save %sp, -16 * 4, %sp ! need all these to preserve
|
| 270 |
|
|
save %sp, -16 * 4, %sp ! the linked list property...
|
| 271 |
|
|
save %sp, -16 * 4, %sp
|
| 272 |
|
|
save %sp, -16 * 4, %sp
|
| 273 |
|
|
#if 6 < __WINSIZE
|
| 274 |
|
|
save %sp, -16 * 4, %sp
|
| 275 |
|
|
#if 7 < __WINSIZE
|
| 276 |
|
|
save %sp, -16 * 4, %sp
|
| 277 |
|
|
#endif
|
| 278 |
|
|
#endif
|
| 279 |
|
|
! Fewer saves if fewer register windows. For 8 register windows,
|
| 280 |
|
|
! six of these is correct; a seventh would force out the current
|
| 281 |
|
|
! set that was already saved manually above. Note that minimal
|
| 282 |
|
|
! space is allowed on stack for locals and ins in case this
|
| 283 |
|
|
! sequence itself gets interrupted and recurses too deep.
|
| 284 |
|
|
|
| 285 |
|
|
! (after all, we are about to call deeper not shallower, otherwise
|
| 286 |
|
|
! using setjmp is inappropriate)
|
| 287 |
|
|
|
| 288 |
|
|
! ENABLE INTERRUPTS
|
| 289 |
|
|
wr %g7, %psr ! set CWP back to as-was
|
| 290 |
|
|
nop
|
| 291 |
|
|
nop
|
| 292 |
|
|
nop
|
| 293 |
|
|
|
| 294 |
|
|
#ifndef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 295 |
|
|
ldd [%o0 + 22 * 4], %g6 ! preserve %g7 and %g6
|
| 296 |
|
|
#endif
|
| 297 |
|
|
|
| 298 |
|
|
retl ! ret and return zero to indicate
|
| 299 |
|
|
mov 0, %o0 ! not longjumped-to
|
| 300 |
|
|
|
| 301 |
|
|
! hal_longjmp loads state from arg0 and returns arg1
|
| 302 |
|
|
!FUNC_START(hal_longjmp)
|
| 303 |
|
|
.global hal_longjmp
|
| 304 |
|
|
hal_longjmp:
|
| 305 |
|
|
! This is kind of a leaf routine, it returns elsewhere
|
| 306 |
|
|
! %o0 is the address of the buffer.
|
| 307 |
|
|
! %o1 is the value to return in %o0 (since we are a leaf)
|
| 308 |
|
|
|
| 309 |
|
|
mov %o0, %g7 ! keep the pointer handy
|
| 310 |
|
|
mov %o1, %g1 ! and the return value
|
| 311 |
|
|
! now select the new window with traps disabled...
|
| 312 |
|
|
rd %psr, %g6
|
| 313 |
|
|
! preserve ET, clear CWP
|
| 314 |
|
|
andn %g6, __WINBITS_MAXIMAL, %g6
|
| 315 |
|
|
andn %g6, 0x20, %g5 ! clear ET also into %g5
|
| 316 |
|
|
|
| 317 |
|
|
! get new CWP from %g0 save place...
|
| 318 |
|
|
ld [%g7 + 16 * 4], %g4 ! %g7 holds the new stack pointer
|
| 319 |
|
|
and %g4, __WINBITS, %g4 ! preserve CWP bits
|
| 320 |
|
|
|
| 321 |
|
|
! calculate a new WIM...
|
| 322 |
|
|
add %g4, 1, %g3 ! required invalid window number
|
| 323 |
|
|
#if 8 == __WINSIZE
|
| 324 |
|
|
and %g3, __WINBITS, %g3 ! modulo 8
|
| 325 |
|
|
#else // expect 5 or 6 or 7 windows
|
| 326 |
|
|
cmp %g3, __WINSIZE
|
| 327 |
|
|
bge,a 567f ! taken: do delay slot, handle overflow
|
| 328 |
|
|
mov 0, %g3 ! only if .ge. above
|
| 329 |
|
|
567:
|
| 330 |
|
|
#endif
|
| 331 |
|
|
mov 1, %g2
|
| 332 |
|
|
sll %g2, %g3, %g2 ! converted to a mask for the WIM
|
| 333 |
|
|
|
| 334 |
|
|
! DISABLE INTERRUPTS
|
| 335 |
|
|
wr %g5, %g4, %psr ! set CWP to new window, disable traps
|
| 336 |
|
|
wr %g2, %wim ! and WIM to new value
|
| 337 |
|
|
nop
|
| 338 |
|
|
nop
|
| 339 |
|
|
nop
|
| 340 |
|
|
|
| 341 |
|
|
! Must do this atomically so that the registers match the stack.
|
| 342 |
|
|
! After locals and ins are loaded, we are conformant to the PCS
|
| 343 |
|
|
! so can re-enable interrupts.
|
| 344 |
|
|
|
| 345 |
|
|
ldd [%g7 + 0 * 4], %l0 ! restore L & I registers
|
| 346 |
|
|
ldd [%g7 + 2 * 4], %l2
|
| 347 |
|
|
ldd [%g7 + 4 * 4], %l4
|
| 348 |
|
|
ldd [%g7 + 6 * 4], %l6
|
| 349 |
|
|
|
| 350 |
|
|
ldd [%g7 + 8 * 4], %i0
|
| 351 |
|
|
ldd [%g7 + 10 * 4], %i2
|
| 352 |
|
|
ldd [%g7 + 12 * 4], %i4
|
| 353 |
|
|
ldd [%g7 + 14 * 4], %i6
|
| 354 |
|
|
|
| 355 |
|
|
ld [%g7 + 30 * 4], %sp ! %o6 = %sp, set up now so as to conform
|
| 356 |
|
|
! to PCS and so be interruptible
|
| 357 |
|
|
! ENABLE INTERRUPTS
|
| 358 |
|
|
wr %g6, %g4, %psr ! set new CWP and old ET
|
| 359 |
|
|
nop
|
| 360 |
|
|
nop
|
| 361 |
|
|
nop
|
| 362 |
|
|
|
| 363 |
|
|
! now load the rest of the context; we can be interrupted here, but
|
| 364 |
|
|
! that is OK, other state will be preserved in that case...
|
| 365 |
|
|
#ifdef CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 366 |
|
|
! we are not preserving globals...
|
| 367 |
|
|
! %o6 = %sp, already set up
|
| 368 |
|
|
ld [%g7 + 31 * 4], %o7 ! "return" address
|
| 369 |
|
|
retl ! %g1 still holds the return value
|
| 370 |
|
|
mov %g1, %o0
|
| 371 |
|
|
|
| 372 |
|
|
#else // load a maximal context
|
| 373 |
|
|
mov %g7, %o0 ! original pointer was in %o0 anyway
|
| 374 |
|
|
|
| 375 |
|
|
ldd [%o0 + 18 * 4], %g2
|
| 376 |
|
|
ldd [%o0 + 20 * 4], %g4
|
| 377 |
|
|
ldd [%o0 + 22 * 4], %g6
|
| 378 |
|
|
|
| 379 |
|
|
ld [%o0 + 25 * 4], %o1 ! %o0 = original pointer
|
| 380 |
|
|
ldd [%o0 + 26 * 4], %o2
|
| 381 |
|
|
ldd [%o0 + 28 * 4], %o4
|
| 382 |
|
|
! %o6 = %sp, already set up
|
| 383 |
|
|
ld [%o0 + 31 * 4], %o7 ! "return" address
|
| 384 |
|
|
|
| 385 |
|
|
! %g1 still holds the return value; want to get this into %o0
|
| 386 |
|
|
! and restore %g1 from the saved state; %o0 is the state pointer:
|
| 387 |
|
|
! g1 = R, o0 = P
|
| 388 |
|
|
xor %o0, %g1, %g1 ! g1 = R^P, o0 = P
|
| 389 |
|
|
xor %o0, %g1, %o0 ! g1 = R^P, o0 = R
|
| 390 |
|
|
xor %o0, %g1, %g1 ! g1 = P, o0 = R all done
|
| 391 |
|
|
|
| 392 |
|
|
retl
|
| 393 |
|
|
ld [%g1 + 17 * 4], %g1 ! and finally restore %g1
|
| 394 |
|
|
#endif // !CYGDBG_HAL_COMMON_CONTEXT_SAVE_MINIMUM
|
| 395 |
|
|
|
| 396 |
|
|
! ------------------------------------------------------------------------------
|
| 397 |
|
|
! end of context.S
|
| 398 |
|
|
|
| 399 |
|
|
|
| 400 |
|
|
|
