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comparison dyncall/dyncall_call_arm32_thumb_gas.s @ 406:351bb41d3bb1

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- removed %-prefixes for register names from arm assembly files (was wrong to begin with, gas accepted them but the clang integrated assembler does not)
author Tassilo Philipp
date Sun, 03 Oct 2021 10:34:56 +0200
parents 00dd15cc5c87
children
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405:e221473a8217 406:351bb41d3bb1
4 Library: dyncall 4 Library: dyncall
5 File: dyncall/dyncall_call_arm32_thumb_gas.s 5 File: dyncall/dyncall_call_arm32_thumb_gas.s
6 Description: ARM Thumb call kernel implementation for GNU assembler. 6 Description: ARM Thumb call kernel implementation for GNU assembler.
7 License: 7 License:
8 8
9 Copyright (c) 2007-2011 Daniel Adler <dadler@uni-goettingen.de>, 9 Copyright (c) 2007-2021 Daniel Adler <dadler@uni-goettingen.de>,
10 Tassilo Philipp <tphilipp@potion-studios.com> 10 Tassilo Philipp <tphilipp@potion-studios.com>
11 11
12 Permission to use, copy, modify, and distribute this software for any 12 Permission to use, copy, modify, and distribute this software for any
13 purpose with or without fee is hereby granted, provided that the above 13 purpose with or without fee is hereby granted, provided that the above
14 copyright notice and this permission notice appear in all copies. 14 copyright notice and this permission notice appear in all copies.
35 .thumb_func 35 .thumb_func
36 dcCall_arm32_thumb: 36 dcCall_arm32_thumb:
37 37
38 /* Prolog. This function never needs to spill inside its prolog, so just store the permanent registers. */ 38 /* Prolog. This function never needs to spill inside its prolog, so just store the permanent registers. */
39 /* Code below is not using high registers, so not storing them in prolog, which is more involved with thumb, anyways. */ 39 /* Code below is not using high registers, so not storing them in prolog, which is more involved with thumb, anyways. */
40 push {%r4-%r7, %r14} /* Frame ptr, permanent registers, link register -> save area on stack. */ 40 push {r4-r7, r14} /* Frame ptr, permanent registers, link register -> save area on stack. */
41 mov %r7, %r13 /* Set frame ptr. */ 41 mov r7, r13 /* Set frame ptr. */
42 sub %r13, #4 /* Realign stack to 8 bytes (b/c we stored 5 regs = 20b). */ 42 sub r13, #4 /* Realign stack to 8 bytes (b/c we stored 5 regs = 20b). */
43 43
44 /* Call. */ 44 /* Call. */
45 mov %r4, %r0 /* Move 'fptr' to r4 (1st argument is passed in r0). */ 45 mov r4, r0 /* Move 'fptr' to r4 (1st argument is passed in r0). */
46 mov %r5, %r1 /* Move 'args' to r5 (2nd argument is passed in r1). */ 46 mov r5, r1 /* Move 'args' to r5 (2nd argument is passed in r1). */
47 mov %r6, %r2 /* Move 'size' to r6 (3rd argument is passed in r2). */ 47 mov r6, r2 /* Move 'size' to r6 (3rd argument is passed in r2). */
48 48
49 cmp %r6, #16 /* Jump to call if no more than 4 arguments. */ 49 cmp r6, #16 /* Jump to call if no more than 4 arguments. */
50 ble call 50 ble call
51 51
52 sub %r6, #16 /* Size of remaining arguments. */ 52 sub r6, #16 /* Size of remaining arguments. */
53 mov %r0, %r13 /* Set stack pointer to top of stack. */ 53 mov r0, r13 /* Set stack pointer to top of stack. */
54 sub %r0, %r0, %r6 54 sub r0, r0, r6
55 lsr %r0, #3 /* Align stack on 8 byte boundaries. */ 55 lsr r0, #3 /* Align stack on 8 byte boundaries. */
56 lsl %r0, #3 56 lsl r0, #3
57 mov %r13, %r0 57 mov r13, r0
58 58
59 add %r1, #16 /* Let r1 point to remaining arguments. */ 59 add r1, #16 /* Let r1 point to remaining arguments. */
60 mov %r2, #0 /* Init byte counter to 0. */ 60 mov r2, #0 /* Init byte counter to 0. */
61 .thumb_func 61 .thumb_func
62 pushArgs: 62 pushArgs:
63 ldrb %r3, [%r1, %r2] /* Load a byte into r3. */ 63 ldrb r3, [r1, r2] /* Load a byte into r3. */
64 strb %r3, [%r0, %r2] /* Push byte onto stack. */ 64 strb r3, [r0, r2] /* Push byte onto stack. */
65 add %r2, %r2, #1 /* Increment byte counter. */ 65 add r2, r2, #1 /* Increment byte counter. */
66 cmp %r2, %r6 66 cmp r2, r6
67 bne pushArgs 67 bne pushArgs
68 .thumb_func 68 .thumb_func
69 call: 69 call:
70 ldmia %r5!, {%r0-%r3} /* Load first 4 arguments for new call into r0-r3. */ 70 ldmia r5!, {r0-r3} /* Load first 4 arguments for new call into r0-r3. */
71 71
72 /* 'blx %r4' workaround for ARMv4t in THUMB: */ 72 /* 'blx r4' workaround for ARMv4t in THUMB: */
73 mov %r6, %r15 /* Load PC+2 instructions from here */ 73 mov r6, r15 /* Load PC+2 instructions from here */
74 add %r6, #5 /* Increment by 2 instructions (Address of 'Epilog') and set bit 0 (THUMB) */ 74 add r6, #5 /* Increment by 2 instructions (Address of 'Epilog') and set bit 0 (THUMB) */
75 mov %r14, %r6 /* Store in link register. */ 75 mov r14, r6 /* Store in link register. */
76 bx %r4 /* Branch and force THUMB-mode return (LR bit 0 set). */ 76 bx r4 /* Branch and force THUMB-mode return (LR bit 0 set). */
77 77
78 /* Epilog. */ 78 /* Epilog. */
79 mov %r13, %r7 /* Reset stack ptr. */ 79 mov r13, r7 /* Reset stack ptr. */
80 pop {%r4-%r7, %r15} /* Restore permanent registers and program counter. (Force a stay in THUMB in ARMv4, whether ARMv5 can return in ARM or THUMB depending on the bit 0. */ 80 pop {r4-r7, r15} /* Restore permanent registers and program counter. (Force a stay in THUMB in ARMv4, whether ARMv5 can return in ARM or THUMB depending on the bit 0. */
81 81