dbmentry.S revision 8008:257eb95aead3 
1
2/* taken from ebfw/rom/dbmentry.s */
3
4#define EB164
5/*#ifndef LINT
6.data
7.asciiz "$Id: dbmentry.s,v 1.1.1.1 1997/10/30 23:27:12 verghese Exp $"
8.text
9#endif
10*/
11/*
12 * Debug Monitor Entry code
13 */
14
15#ifndef MAKEDEPEND
16#include "ev5_impure.h"
17#include "cserve.h"
18#include "fromHudsonOsf.h"
19#endif
20
21//#include "paldefs.h"
22#include "regdefs.h"
23#include "eb164.h"
24//#include "ledcodes.h"
25
26        .text
27
28/* return address and padding to octaword align */
29#define STARTFRM 16
30
31        .globl  __start
32        .ent    __start, 0
33__start:
34_entry:
35        br      t0, 2f			# get the current PC
362:	ldgp    gp, 0(t0)               # init gp
37
38
39#ifdef original_xxm
40        lda	a2, CSERVE_K_RD_IMPURE
41        call_pal PAL_CSERVE_ENTRY
42        lda	v0,  CNS_Q_BASE(v0)
43
44        # Add KSEG offset to the impure area
45        subq	zero, 1, t0
46        sll	t0, 42, t0
47        addq	t0, v0, v0
48
49        lda	t0, CNS_Q_SIGNATURE(v0)
50        bic 	t0, 0x07, t0		# Clear bottom 3 bits to avoid
51                                        # allignment errors if the
52                                        # impure area is total rubbish
53        ldq	t0, 0x00(t0)
54        srl	t0, 16, t0		# Shift signature into bottom 16 bits.
55        lda	t6, 0xDECB(zero)	# Load the expected valid signature.
56        zap	t6, 0xFC, t6		# Clear the upper bits.
57        cmpeq	t0, t6, t0		# Is this a valid signature?
58        beq	t0, 1f			# Not valid, don't trust input params.
59
60/*
61 *	Init the stack at the first 8K boundary
62 *	below the top of memory.
63 */
64        lda	t0, CNS_Q_MEM_SIZE(v0)
65        ldq	t0, 0x00(t0)		# Load memory size.
66        subq	t0, 1, t0		# Last address in memory
67        srl	t0, 13, t0		# Align to first 8KB boundary
68        sll	t0, 13, sp		# below the top of memory.
69        br	zero, 2f
70
71/*
72 *	If memory size was not passed in via the
73 *	PALcode impure data use the system specific
74 *	MINIMUM_SYSTEM_MEMORY definition.
75 */
761:
77        lda	sp, (MINIMUM_SYSTEM_MEMORY&0xffff)(zero)
78        ldah	sp, ((MINIMUM_SYSTEM_MEMORY+0x8000)>>16)(sp)
79        lda	t0, (8*1024)(zero)	# Allow for 8KB guard page.
80        subq	sp, t0, sp
81
822:
83
84#endif /* original_xxm */
85
86
87        /*
88         * SimOS. Stack pointer is start of a valid phys or KSEG page
89         */
90
91        bis	sp,sp,s0 /* save sp */
92
93slave:	lda	v0,(8*1024)(sp) /* end of page  */
94
95        subq	zero, 1, t0
96        sll	t0, 42, t0
97        bis	t0, v0, sp
98
99#ifdef original_xxm
100        # Add KSEG offset to the stack pointer
101        subq	zero, 1, t0
102        sll	t0, 42, t0
103        addq	t0, sp, sp
104#endif
105
106        lda     sp, -STARTFRM(sp)	# Create a stack frame
107        stq     ra, 0(sp)		# Place return address on the stack
108
109        .mask   0x84000000, -8
110        .frame  sp, STARTFRM, ra
111
112/*
113 *	Enable the Floating Point Unit
114 */
115        lda	a0, 1(zero)
116        call_pal PAL_WRFEN_ENTRY
117
118/*
119 *	Every good C program has a main()
120 */
121
122        beq	s0,master
123
124        call_pal PAL_WHAMI_ENTRY
125        bis	v0,v0,a0
126        jsr	ra, SlaveLoop
127master:
128        jsr	ra, main
129
130
131
132/*
133 *	The Debug Monitor should never return.
134 *	However, just incase...
135 */
136        ldgp	gp, 0(ra)
137        bsr	zero, _exit
138
139.end	__start
140
141
142
143        .globl  _exit
144        .ent    _exit, 0
145_exit:
146
147        ldq     ra, 0(sp)		# restore return address
148        lda	sp, STARTFRM(sp)	# prune back the stack
149        ret	zero, (ra)		# Back from whence we came
150.end	_exit
151
152                .globl	cServe
153        .ent	cServe 2
154cServe:
155        .option	O1
156        .frame	sp, 0, ra
157        call_pal PAL_CSERVE_ENTRY
158        ret	zero, (ra)
159        .end	cServe
160
161        .globl	wrfen
162        .ent	wrfen 2
163wrfen:
164        .option	O1
165        .frame	sp, 0, ra
166        call_pal PAL_WRFEN_ENTRY
167        ret	zero, (ra)
168        .end	wrfen
169        .globl	consoleCallback
170        .ent	consoleCallback 2
171consoleCallback:
172        br      t0, 2f			# get the current PC
1732:	ldgp    gp, 0(t0)               # init gp
174        lda     sp,-64(sp)
175        stq     ra,0(sp)
176        jsr     CallBackDispatcher
177        ldq     ra,0(sp)
178        lda     sp,64(sp)
179        ret     zero,(ra)
180        .end    consoleCallback
181
182
183        .globl	consoleFixup
184        .ent	consoleFixup 2
185consoleFixup:
186        br      t0, 2f			# get the current PC
1872:	ldgp    gp, 0(t0)               # init gp
188        lda     sp,-64(sp)
189        stq     ra,0(sp)
190        jsr     CallBackFixup
191        ldq     ra,0(sp)
192        lda     sp,64(sp)
193        ret     zero,(ra)
194        .end    consoleFixup
195
196
197
198        .globl	SpinLock
199        .ent	SpinLock 2
200SpinLock:
2011:
202        ldq_l	a1,0(a0)		# interlock complete lock state
203        subl	ra,3,v0			# get calling addr[31:0] + 1
204        blbs	a1,2f			# branch if lock is busy
205        stq_c	v0,0(a0)		# attempt to acquire lock
206        beq	v0,2f			# branch if lost atomicity
207        mb				# ensure memory coherence
208        ret	zero,(ra)		# return to caller (v0 is 1)
2092:
210        br	zero,1b
211        .end	SpinLock
212
213        .globl	loadContext
214        .ent	loadContext 2
215loadContext:
216        .option	O1
217        .frame	sp, 0, ra
218        call_pal PAL_SWPCTX_ENTRY
219        ret	zero, (ra)
220        .end	loadContext
221
222
223        .globl	SlaveSpin          # Very carefully spin wait
224        .ent	SlaveSpin 2        # and swap context without
225SlaveSpin:                         # using any stack space
226        .option	O1
227        .frame	sp, 0, ra
228        mov a0, t0                 # cpu number
229        mov a1, t1                 # cpu rpb pointer (virtual)
230        mov a2, t2                 # what to spin on
231
232test:   ldl  t3, 0(t2)
233        beq  t3, test
234        zapnot t1,0x1f,a0          # make rpb physical
235        call_pal PAL_SWPCTX_ENTRY  # switch to pcb
236        mov t0, a0                 # setup args for SlaveCmd
237        mov t1, a1
238        jsr SlaveCmd               # call SlaveCmd
239        ret	zero, (ra)         # Should never be reached
240        .end	SlaveSpin
241
242
243