/*
Copyright Oliver Kowalke 2009.
Distributed under the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or copy at
http://www.boost.org/LICENSE_1_0.txt)
*/
/*******************************************************
* *
* ------------------------------------------------- *
* | 0 | 4 | 8 | 12 | 16 | 20 | 24 | 28 | *
* ------------------------------------------------- *
* |bchai| CR | LR |compl| link| TOC | R14 | R15 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 32 | 36 | 40 | 44 | 48 | 52 | 56 | 60 | *
* ------------------------------------------------- *
* | R16 | R17 | R18 | R19 | R20 | R21 | R22 | R23 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 64 | 68 | 72 | 76 | 80 | 84 | 88 | 92 | *
* ------------------------------------------------- *
* | R24 | R25 | R26 | R27 | R28 | R29 | R30 | R31 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 96 | 100 | 104 | 108 | 112 | 116 | 120 | 124 | *
* ------------------------------------------------- *
* | F14 | F15 | F16 | F17 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 128 | 132 | 136 | 140 | 144 | 148 | 152 | 156 | *
* ------------------------------------------------- *
* | F18 | F19 | F20 | F21 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 160 | 164 | 168 | 172 | 176 | 180 | 184 | 188 | *
* ------------------------------------------------- *
* | F22 | F23 | F24 | F25 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 192 | 196 | 200 | 204 | 208 | 212 | 216 | 220 | *
* ------------------------------------------------- *
* | F26 | F27 | F28 | F29 | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 224 | 228 | 232 | 236 | 240 | 244 | 248 | 252 | *
* ------------------------------------------------- *
* | F30 | F31 | PC |hiddn| fpscr | *
* ------------------------------------------------- *
* ------------------------------------------------- *
* | 256 | 260 | 264 | 268 | 272 | 276 | 280 | 284 | *
* ------------------------------------------------- *
* |bchai|savLR|savLR|compl| link|svTOC| FCTX| DATA| *
* ------------------------------------------------- *
* *
*******************************************************/
.file "ontop_ppc32_sysv_xcoff_xas.S"
.toc
.csect .text[PR]
.align 2
.globl ontop_fcontext[DS]
.globl .ontop_fcontext
.csect ontop_fcontext[DS]
ontop_fcontext:
.long .ontop_fcontext[PR], TOC[tc0], 0
.csect .text[PR], 5
.ontop_fcontext:
# reserve space on stack
subi 1, 1, 256
# save CR
mfcr 0
stw 0, 4(1)
# save LR
mflr 0
stw 0, 8(1)
# save LR as PC
stw 0, 240(1)
# save TOC
stw 2, 20(1)
# Save registers R14 to R31.
stw 14, 24(1)
stw 15, 28(1)
stw 16, 32(1)
stw 17, 36(1)
stw 18, 40(1)
stw 19, 44(1)
stw 20, 48(1)
stw 21, 52(1)
stw 22, 56(1)
stw 23, 60(1)
stw 24, 64(1)
stw 25, 68(1)
stw 26, 72(1)
stw 27, 76(1)
stw 28, 80(1)
stw 29, 84(1)
stw 30, 88(1)
stw 31, 92(1)
# Save registers F14 to F31 in slots with 8-byte alignment.
# 4-byte alignment may stall the pipeline of some processors.
# Less than 4 may cause alignment traps.
stfd 14, 96(1)
stfd 15, 104(1)
stfd 16, 112(1)
stfd 17, 120(1)
stfd 18, 128(1)
stfd 19, 136(1)
stfd 20, 144(1)
stfd 21, 152(1)
stfd 22, 160(1)
stfd 23, 168(1)
stfd 24, 176(1)
stfd 25, 184(1)
stfd 26, 192(1)
stfd 27, 200(1)
stfd 28, 208(1)
stfd 29, 216(1)
stfd 30, 224(1)
stfd 31, 232(1)
# hidden pointer
stw 3, 244(1)
mffs 0 # load FPSCR
stfd 0, 248(1) # save FPSCR
# store RSP (pointing to context-data) in R7
mr 7, 1
# restore RSP (pointing to context-data) from R4
mr 1, 4
# restore CR
lwz 0, 4(1)
mtcr 0
# restore R14 to R31
lwz 14, 24(1)
lwz 15, 28(1)
lwz 16, 32(1)
lwz 17, 36(1)
lwz 18, 40(1)
lwz 19, 44(1)
lwz 20, 48(1)
lwz 21, 52(1)
lwz 22, 56(1)
lwz 23, 60(1)
lwz 24, 64(1)
lwz 25, 68(1)
lwz 26, 72(1)
lwz 27, 76(1)
lwz 28, 80(1)
lwz 29, 84(1)
lwz 30, 88(1)
lwz 31, 92(1)
# restore F14 to F31
lfd 14, 96(1)
lfd 15, 104(1)
lfd 16, 112(1)
lfd 17, 120(1)
lfd 18, 128(1)
lfd 19, 136(1)
lfd 20, 144(1)
lfd 21, 152(1)
lfd 22, 160(1)
lfd 23, 168(1)
lfd 24, 176(1)
lfd 25, 184(1)
lfd 26, 192(1)
lfd 27, 200(1)
lfd 28, 208(1)
lfd 29, 216(1)
lfd 30, 224(1)
lfd 31, 232(1)
lwz 3, 244(1) # restore hidden
lfd 0, 248(1) # load FPSCR
mtfsf 0xff, 0 # restore FPSCR
# copy transfer_t into ontop_fn arg registers
mr 4, 7
# arg pointer already in r5
# hidden arg already in r3
# restore CTR
lwz 7, 0(6)
mtctr 7
# restore TOC
lwz 2, 4(6)
# zero in r3 indicates first jump to context-function
cmpdi 3, 0
beq use_entry_arg
return_to_ctx:
# restore LR
lwz 0, 8(1)
mtlr 0
# adjust stack
addi 1, 1, 256
# jump to context
bctr
use_entry_arg:
# compute return-value struct address
# (passed has hidden arg to ontop_fn)
addi 3, 1, 8
# jump to context and update LR
bctrl
# restore CTR
lwz 7, 4(1)
mtctr 7
# restore TOC
lwz 2, 20(1)
# copy returned transfer_t into entry_fn arg registers
lwz 3, 8(1)
lwz 4, 12(1)
b return_to_ctx