Repo init

lab2/Makefile

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+all: mul_arm
+
+mul_arm: mul.s
+	gcc mul.s -o mul_arm
+
+clean:
+	rm mul_arm

lab2/mul.s

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+SYSEXIT = 1
+SYSREAD = 3
+SYSWRITE = 4
+STDIN = 0
+STDOUT = 1
+
+num_length = 256
+word_length = 4
+buf_length = num_length * 2
+num_words = num_length / word_length
+buf_words = buf_length / word_length
+
+.global main
+
+.bss
+num1: .space num_length
+num2: .space num_length
+result: .space buf_length
+
+.text
+main:
+loop:
+mov r7, #SYSREAD
+mov r0, #STDIN
+ldr r1, =num1
+mov r2, #buf_length
+swi 0x0
+
+cmp r0, #buf_length
+blt end
+
+ldr r8, =num1
+ldr r9, =num2
+ldr r10, =result
+
+eor r0, r0, r0
+
+eor r4, r4, r4
+
+zero:
+str r0, [r10, r4, lsl#2]
+add r4, r4, #1
+cmp r4, #buf_words
+blt zero
+
+eor r4, r4, r4
+
+loop1:
+eor r11, r11, r11
+eor r12, r12, r12
+
+eor r2, r2, r2
+
+eor r5, r5, r5
+
+loop2:
+ldr r0, [r8, r4, lsl#2]
+ldr r3, [r9, r5, lsl#2]
+umull r0, r1, r0, r3
+
+msr apsr_nzcvq, r11
+adcs r0, r0, r2
+mrs r11, apsr
+
+mov r2, r1
+add r6, r4, r5
+
+msr apsr_nzcvq, r12
+ldr r1, [r10, r6, lsl#2]
+adcs r1, r0, r1
+str r1, [r10, r6, lsl#2]
+mrs r12, apsr
+
+add r5, r5, #1
+cmp r5, #num_words
+blt loop2
+
+add r6, r6, #1
+
+msr apsr_nzcvq, r11
+adc r2, r2, #0
+
+msr apsr_nzcvq, r12
+ldr r1, [r10, r6, lsl#2]
+adc r1, r1, r2
+str r1, [r10, r6, lsl#2]
+
+add r4, r4, #1
+cmp r4, #num_words
+blt loop1
+
+mov r7, #SYSWRITE
+mov r0, #STDOUT
+ldr r1, =result
+mov r2, #buf_length
+swi 0x0
+
+b loop
+
+end:
+mov r7, #SYSEXIT
+mov r0, #0
+swi 0x0