1 // Copyright 2013, ARM Limited
2 // All rights reserved.
3 //
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5 // modification, are permitted provided that the following conditions are met:
6 //
7 // * Redistributions of source code must retain the above copyright notice,
8 // this list of conditions and the following disclaimer.
9 // * Redistributions in binary form must reproduce the above copyright notice,
10 // this list of conditions and the following disclaimer in the documentation
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13 // used to endorse or promote products derived from this software without
14 // specific prior written permission.
15 //
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25 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27 #include "examples.h"
28
29 #define BUF_SIZE (4096)
30 #define __ masm->
31
GenerateSwapInt32(MacroAssembler * masm)32 void GenerateSwapInt32(MacroAssembler* masm) {
33 {
34 // In this scope the register x2 will be used by the macro-assembler
35 // as the stack pointer (via peek, poke, push, etc).
36 const Register old_stack_pointer = __ StackPointer();
37 __ Mov(x2, __ StackPointer());
38 __ SetStackPointer(x2);
39
40 // This call to Claim is not 16-byte aligned and would have failed
41 // if the current stack pointer was sp.
42 __ Claim(8);
43
44 __ Poke(w0, 0);
45 __ Poke(w1, 4);
46 __ Peek(w1, 0);
47 __ Peek(w0, 4);
48
49 __ Drop(8);
50
51 // Even if we didn't use the system stack pointer, sp might have been
52 // modified because the ABI forbids access to memory below the stack
53 // pointer.
54 __ Mov(old_stack_pointer, __ StackPointer());
55 __ SetStackPointer(old_stack_pointer);
56 }
57
58 // The stack pointer has now been switched back to sp.
59 __ Ret();
60 }
61
62
63 #ifndef TEST_EXAMPLES
main(void)64 int main(void) {
65 // Create and initialize the assembler and the simulator.
66 byte assm_buf[BUF_SIZE];
67 MacroAssembler masm(assm_buf, BUF_SIZE);
68 Decoder decoder;
69 Simulator simulator(&decoder);
70
71 // Generate the code for the example function.
72 Label swap_int32;
73 masm.Bind(&swap_int32);
74 GenerateSwapInt32(&masm);
75 masm.FinalizeCode();
76
77 // Run the example function.
78 simulator.set_wreg(0, 0x11111111);
79 simulator.set_wreg(1, 0x22222222);
80
81 printf("Before swap_int32:\n"
82 "x0 = 0x%" PRIx32 "\n"
83 "x1 = 0x%" PRIx32 "\n",
84 simulator.wreg(0), simulator.wreg(1));
85
86 simulator.RunFrom(swap_int32.target());
87
88 printf("After swap_int32:\n"
89 "x0 = 0x%" PRIx32 "\n"
90 "x1 = 0x%" PRIx32 "\n",
91 simulator.wreg(0), simulator.wreg(1));
92
93 return 0;
94 }
95 #endif
96