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// ================================================================================================
// Code written while reading chapter 11 of Modern Arm Assembly Language Programming
//
// License:
// SPDX-License-Identifier: 0BSD
// Copyright (c) 2026 Hunter Kvalevog
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE.
// ================================================================================================
#include "common.S"
TEXT_SEGMENT
// example 1
.global SYM(i32_add_sub)
.global SYM(i64_add_sub)
SYM(i32_add_sub):
// w0: a
// w1: b
// w2: c
#if 0
add w3, w0, w1
sub w0, w3, w2
#else
add w0, w0, w1
sub w0, w0, w2
#endif
// w0: return
ret
SYM(i64_add_sub):
// x0: a
// x1: b
// x2: c
add x3, x0, x1
sub x0, x3, x2
// x0: return
ret
// example 2
.global SYM(i32_mul)
.global SYM(i32_mul_safe)
SYM(i32_mul):
// w0: a
// w1: b
mul w0, w0, w1
// w0: return
ret
SYM(i32_mul_safe):
// w0: a
// w1: b
smull x0, w0, w1
// x0: ret
ret
// example 3
.global SYM(i32_quo_rem)
SYM(i32_quo_rem):
// w0: num
// w1: den
// x2: *quo
// x3: *den
// calculate quotient
sdiv w4, w0, w1
str w4, [x2]
// calculate remainder
mul w5, w1, w4
sub w6, w0, w5
str w6, [x3]
ret
// example 4
.global SYM(test_ldr1)
SYM(test_ldr1):
// w0: i
// x1: j
// x2: tab
ldr w3, [x2, w0, uxtw #2] // tab[i] (32-bit index)
ldr w4, [x2, x1, lsl #2] // tab[j] (64-bit index)
add w0, w3, w4
ret
// example 5
.global SYM(test_mov1)
SYM(test_mov1):
// x0: *out
.equ BIGNUM,0xABCD1234
.equ BIGNUM_LO16,((BIGNUM & 0x0000FFFF) >> 0)
.equ BIGNUM_HI16,((BIGNUM & 0xFFFF0000) >> 16)
mov w2, #BIGNUM_LO16
movk w2, #BIGNUM_HI16, lsl 16
str w2, [x0] // out[0] = w2
movz w3, #BIGNUM_LO16, lsl 16
str w3, [x0, #4] // out[1] = w3
movz w4, 0x1234
str w4, [x0, #8] // out[2] = w4
ret
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