1#define nop andeq r0, r0
 2
 3.text
 4
 5b resetBase
 6b undefBase
 7b swiBase
 8b pabtBase
 9b dabtBase
10nop
11b irqBase
12b fiqBase
13
14resetBase:
15mov pc, #0x8000000
16
17swiBase:
18cmp    sp, #0
19moveq  sp, #0x04000000
20subeq  sp, #0x20
21stmfd  sp!, {r2, lr}
22ldrb   r2, [lr, #-2]
23cmp    r2, #4
24bleq   IntrWait
25cmp    r2, #5
26moveq  r0, #1
27moveq  r1, #1
28bleq   IntrWait
29ldmfd  sp!, {r2, lr}
30movs   pc, lr
31
32irqBase:
33stmfd  sp!, {r0-r3, r12, lr}
34mov    r0, #0x04000000
35add    lr, pc, #0
36ldr    pc, [r0, #-4]
37ldmfd  sp!, {r0-r3, r12, lr}
38subs   pc, lr, #4
39
40IntrWait:
41stmfd  sp!, {r4, lr}
42# Save inputs
43mrs    r3, cpsr
44bic    r3, #0x80
45msr    cpsr, r3
46# Pull current interrupts enabled and add the ones we need
47mov    r4, #0x04000000
48# See if we want to return immediately
49cmp    r0, #0
50mov    r0, #0
51mov    r2, #1
52beq    .L1
53# Halt
54.L0:
55strb   r0, [r4, #0x301]
56.L1:
57# Check which interrupts were acknowledged
58strb   r2, [r4, #0x204]
59ldrh   r3, [r4, #-8]
60ands   r3, r1
61eorne  r3, r1
62strneh r3, [r4, #-8]
63strb   r0, [r4, #0x204]
64beq .L0
65#Restore state
66mrs    r0, cpsr
67orr    r0, #0x80
68msr    cpsr, r0
69ldmfd  sp!, {r4, pc}