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41 lines
1.4 KiB
ArmAsm
41 lines
1.4 KiB
ArmAsm
.global main // Expose 'main' to the linker.
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.text // Specify what comes next is code.
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/* Perry Kivolowitz
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Assembly Language Programming Made Not So Scary
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if06.s - demonstrating an IF statement.
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This program will compare 5 to 10. If 5 is larger
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(it isn't), the program will print TRUE. If 10 is
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larger than 5 (it is), the program will print
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FALSE.
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*/
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main:
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str x30, [sp, -16]! // Preserve x30 due to function call.
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mov x1, 10 // b gets 10
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mov x0, 5 // a gets 5
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cmp x0, x1 // a - b ... 5 - 10 makes negative 5.
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ble 1f // If b >= a, thake the branch.
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ldr x0, =T // a is greather than b - load the
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// address of TRUE string into x0
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b 2f // Skip over prepping FALSE
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1: ldr x0, =F // x0 contains a pointer to the
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// correct string either way.
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2: bl puts // Print the string with a new line.
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ldr x30, [sp], 16 // Restore x30 so we can return.
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mov x0, xzr // Indicate success to the caller.
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ret // Return back to the caller.
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.data // What comes next is data.
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F: .asciz "FALSE" // Null terminated C string.
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T: .asciz "TRUE" // Null terminated C string.
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.end // Tells the assembler that it
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// should emit an error if any
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// more data or instructions
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// come after.
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