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https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-26 19:51:35 +01:00
52 lines
1.0 KiB
ArmAsm
52 lines
1.0 KiB
ArmAsm
/* https://github.com/cirosantilli/arm-assembly-cheat#addressing-modes */
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#include "common.h"
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ENTRY
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/* Offset mode with immediate. Add 4 to the address register, which ends up
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* reading myvar2 instead of myvar.
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*/
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adr r0, myvar
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ldr r1, [r0, 4]
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ASSERT_EQ(r1, 0x9ABCDEF0)
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/* r0 was not modified. */
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ASSERT_EQ(r0, myvar)
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/* Pre-indexed mode */
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adr r0, myvar
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ldr r1, [r0, 4]!
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ASSERT_EQ(r1, 0x9ABCDEF0)
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/* r0 was modified. */
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ASSERT_EQ(r0, myvar2)
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/* Post-indexed mode */
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adr r0, myvar
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ldr r1, [r0], 4
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ASSERT_EQ(r1, 0x12345678)
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/* r0 was modified. */
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ASSERT_EQ(r0, myvar2)
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/* Offset in register. */
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adr r0, myvar
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mov r1, 4
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ldr r2, [r0, r1]
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ASSERT_EQ(r2, 0x9ABCDEF0)
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/* Offset in shifted register:
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* r2 =
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* (r0 + (r1 << 1))
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* == *(myvar + (2 << 1))
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* == *(myvar + 4)
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*/
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adr r0, myvar
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mov r1, 2
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ldr r2, [r0, r1, lsl 1]
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ASSERT_EQ(r2, 0x9ABCDEF0)
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EXIT
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myvar:
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.word 0x12345678
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myvar2:
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.word 0x9ABCDEF0
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