Context Navigation

window.S @ 8b5778e

Last change on this file since 8b5778e was 8b5778e, checked in by Sebastian Huber <sebastian.huber@…>, on 03/12/18 at 05:37:36

sparc: Move libcpu content to cpukit

This patch is a part of the BSP source reorganization.

Update #3285.

Property mode set to 100644

File size: 8.4 KB

Line
1	/*
2	* window.s
3	*
4	* This file contains the register window management routines for the
5	* SPARC architecture. Trap handlers for the following capabilities
6	* are included in this file:
7	*
8	* + Window Overflow
9	* + Window Underflow
10	* + Flushing All Windows
11	*
12	* COPYRIGHT:
13	*
14	* This file includes the window overflow and underflow handlers from
15	* the file srt0.s provided with the binary distribution of the SPARC
16	* Instruction Simulator (SIS) found at
17	* ftp://ftp.estec.esa.nl/pub/ws/wsd/erc32.
18	*
19	* COPYRIGHT (c) 1995. European Space Agency.
20	*
21	* This terms of the RTEMS license apply to this file.
22	*/
23
24	#include <rtems/asm.h>
25
26	.section ".text"
27	/*
28	* Window overflow trap handler.
29	*
30	* On entry:
31	*
32	* prev regwin l1 = pc
33	* prev regwin l2 = npc
34	*/
35
36	PUBLIC(window_overflow_trap_handler)
37
38	SYM(window_overflow_trap_handler):
39
40	/*
41	* Calculate new WIM by "rotating" the valid bits in the WIM right
42	* by one position. The following shows how the bits move for a SPARC
43	* cpu implementation where SPARC_NUMBER_OF_REGISTER_WINDOWS is 8.
44	*
45	* OLD WIM = 76543210
46	* NEW WIM = 07654321
47	*
48	* NOTE: New WIM must be stored in a global register since the
49	* "save" instruction just prior to the load of the wim
50	* register will result in the local register set changing.
51	*/
52
53	std %l0, [%sp + 0x00] ! save local register set
54	SPARC_LEON3FT_B2BST_NOP
55	std %l2, [%sp + 0x08]
56	mov %wim, %l3
57	sll %l3, SPARC_NUMBER_OF_REGISTER_WINDOWS-1 , %l2
58	! l2 = WIM << (Number Windows - 1)
59	std %l4, [%sp + 0x10]
60	SPARC_LEON3FT_B2BST_NOP
61	std %l6, [%sp + 0x18]
62	srl %l3, 1, %l3 ! l3 = WIM >> 1
63	wr %l3, %l2, %wim ! WIM = (WIM >> 1) ^
64	! (WIM << (Number Windows - 1))
65	! 3 instruction delay not needed here
66	std %i0, [%sp + 0x20] ! save input register set
67	SPARC_LEON3FT_B2BST_NOP
68	std %i2, [%sp + 0x28]
69	SPARC_LEON3FT_B2BST_NOP
70	std %i4, [%sp + 0x30]
71	SPARC_LEON3FT_B2BST_NOP
72	std %i6, [%sp + 0x38]
73	restore ! Go back to trap window.
74	jmp %l1 ! Re-execute save.
75	rett %l2
76
77	/*
78	* Window underflow trap handler.
79	*
80	* On entry:
81	*
82	* l1 = pc
83	* l2 = npc
84	* l3 = wim (from trap vector)
85	* l4 = wim << 1 (from trap vector)
86	*/
87
88	PUBLIC(window_underflow_trap_handler)
89
90	SYM(window_underflow_trap_handler):
91
92	/*
93	* Calculate new WIM by "rotating" the valid bits in the WIM left
94	* by one position. The following shows how the bits move for a SPARC
95	* cpu implementation where SPARC_NUMBER_OF_REGISTER_WINDOWS is 8.
96	*
97	* OLD WIM = 76543210
98	* NEW WIM = 07654321
99	*
100	* NOTE: New WIM must be stored in a global register since the
101	* "save" instruction just prior to the load of the wim
102	* register will result in the local register set changing.
103	*/
104
105	srl %l3, SPARC_NUMBER_OF_REGISTER_WINDOWS-1, %l5
106	or %l5, %l4, %l5 ! l5 = (WIM << 1) \|
107	! (WIM >> (Number Windows-1))
108	mov %l5, %wim ! load the new WIM
109	nop; nop; nop ! 3 slot delay
110	restore ! Two restores to get into the
111	restore ! window to restore
112	ldd [%sp + 0x00], %l0 ! First the local register set
113	ldd [%sp + 0x08], %l2
114	ldd [%sp + 0x10], %l4
115	ldd [%sp + 0x18], %l6
116	ldd [%sp + 0x20], %i0 ! Then the input registers
117	ldd [%sp + 0x28], %i2
118	ldd [%sp + 0x30], %i4
119	ldd [%sp + 0x38], %i6
120	save ! Get back to the trap window.
121	save
122	jmp %l1 ! Re-execute restore.
123	rett %l2
124
125	/*
126	* Flush All Windows trap handler.
127	*
128	* Flush all windows with valid contents except the current one
129	* and the one we will be returning to.
130	*
131	* In examining the set register windows, one may logically divide
132	* the windows into sets (some of which may be empty) based on their
133	* current status:
134	*
135	* + current (i.e. in use),
136	* + used (i.e. a restore would not trap)
137	* + invalid (i.e. 1 in corresponding bit in WIM)
138	* + unused
139	*
140	* Either the used or unused set of windows may be empty.
141	*
142	* NOTE: We assume only one bit is set in the WIM at a time.
143	*
144	* Given a CWP of 5 and a WIM of 0x1, the registers are divided
145	* into sets as follows:
146	*
147	* + 0 - invalid
148	* + 1-4 - unused
149	* + 5 - current
150	* + 6-7 - used
151	*
152	* In this case, we only would save the used windows which we
153	* will not be returning to -- 6.
154	*
155	* Register Usage while saving the windows:
156	* g1 = current PSR
157	* g2 = current wim
158	* g3 = CWP
159	* g4 = wim scratch
160	* g5 = scratch
161	*
162	* On entry:
163	*
164	* l0 = psr (from trap table)
165	* l1 = pc
166	* l2 = npc
167	*/
168
169	PUBLIC(window_flush_trap_handler)
170
171	SYM(window_flush_trap_handler):
172	/*
173	* Save the global registers we will be using
174	*/
175
176	mov %g1, %l3
177	mov %g2, %l4
178	mov %g3, %l5
179	mov %g4, %l6
180	mov %g5, %l7
181
182	mov %l0, %g1 ! g1 = psr
183	mov %wim, %g2 ! g2 = wim
184	and %l0, SPARC_PSR_CWP_MASK, %g3 ! g3 = CWP
185
186	add %g3, 1, %g5 ! g5 = CWP + 1
187	and %g5, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g5
188
189	mov 1, %g4
190	sll %g4, %g5, %g4 ! g4 = WIM mask for CWP+1 invalid
191
192	restore ! go back one register window
193
194	save_frame_loop:
195	sll %g4, 1, %g5 ! rotate the "wim" left 1
196	srl %g4, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g4
197	or %g4, %g5, %g4 ! g4 = wim if we do one restore
198
199	/*
200	* If a restore would not underflow, then continue.
201	*/
202
203	andcc %g4, %g2, %g0 ! Any windows to flush?
204	bnz done_flushing ! No, then continue
205	nop
206
207	restore ! back one window
208
209	/*
210	* Now save the window just as if we overflowed to it.
211	*/
212
213	std %l0, [%sp + CPU_STACK_FRAME_L0_OFFSET]
214	SPARC_LEON3FT_B2BST_NOP
215	std %l2, [%sp + CPU_STACK_FRAME_L2_OFFSET]
216	SPARC_LEON3FT_B2BST_NOP
217	std %l4, [%sp + CPU_STACK_FRAME_L4_OFFSET]
218	SPARC_LEON3FT_B2BST_NOP
219	std %l6, [%sp + CPU_STACK_FRAME_L6_OFFSET]
220	SPARC_LEON3FT_B2BST_NOP
221
222	std %i0, [%sp + CPU_STACK_FRAME_I0_OFFSET]
223	SPARC_LEON3FT_B2BST_NOP
224	std %i2, [%sp + CPU_STACK_FRAME_I2_OFFSET]
225	SPARC_LEON3FT_B2BST_NOP
226	std %i4, [%sp + CPU_STACK_FRAME_I4_OFFSET]
227	SPARC_LEON3FT_B2BST_NOP
228	std %i6, [%sp + CPU_STACK_FRAME_I6_FP_OFFSET]
229
230	ba save_frame_loop
231	nop
232
233	done_flushing:
234
235	add %g3, 2, %g3 ! calculate desired WIM
236	and %g3, SPARC_NUMBER_OF_REGISTER_WINDOWS - 1, %g3
237	mov 1, %g4
238	sll %g4, %g3, %g4 ! g4 = new WIM
239	mov %g4, %wim
240
241	mov %g1, %psr ! restore PSR
242	nop
243	nop
244	nop
245
246	/*
247	* Restore the global registers we used
248	*/
249
250	mov %l3, %g1
251	mov %l4, %g2
252	mov %l5, %g3
253	mov %l6, %g4
254	mov %l7, %g5
255
256	jmpl %l2, %g0
257	rett %l2 + 4
258
259	/* end of file */

Note: See TracBrowser for help on using the repository browser.

Download in other formats:

Original Format