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86de75098a
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lab1_v2.S
52
lab1_v2.S
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@ -2,50 +2,26 @@
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.cpu cortex-m4
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.thumb
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.macro BKPT_WRITE addr_src
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mov r1, \addr_src
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mov r0, 0x4
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bkpt 0xAB
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.endm
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.section .data
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test_string: .asciz "Hello"
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.section .text
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lab1_v2:
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push.n {lr}
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sub sp, #6
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ldr r0, =test_string
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mov r1, #5
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mov r0, #2073
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bl int_to_str
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copy_loop:
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ldrb r2, [r0, r1]
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strb r2, [sp, r1]
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subs r1, #1
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bpl copy_loop
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pop.n {pc}
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mov r1, sp
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mov r0, 0x04
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bkpt 0xAB
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int_to_str:
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mov r3, sp
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@ write newline + NULL terminator
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mov r5, #0x000A
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strh r5, [r3, #-2]!
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@ --- handmade modulo ---
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mov r4, #10
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iterate:
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mov r1, r0 @ save orig to r1
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udiv r0, r0, r4 @ orig/10 and overwrite old orig value
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mul r2, r0, r4 @ orig/10*10, place separately
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subs r5, r1, r2 @ orig - orig/10*10 => modulo (and update flags)
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beq check_if_pending_digits_exist
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proceed_with_conversion:
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add r5, #48 @ int -> char (only digits, so it's fine)
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strb r5, [r3, #-1]! @ write next char to RAM
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b iterate
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check_if_pending_digits_exist:
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cmp r0, #0
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bne proceed_with_conversion
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finish:
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BKPT_WRITE r3
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add sp, #6
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mov pc, lr
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