| .text | |
| mov r6, #0x100 @ base memory address | |
| mov r0, #0 @ r0 = low-order word of result | |
| mov r1, #0 @ r1 = high-order word of result | |
| mov r2, #0x69 @ r2<-low-order word of multiplicand | |
| str r2, [r6, #0x10] @ store multiplicand | |
| mov r3, #0x0 @ r3<-high-order word of multiplicand | |
| mov r4, #0x5a @ load multiplier | |
| str r4, [r6, #0x24] @ store multiplicand | |
| mov r5, #0 | |
| loop: tst r4, #1 @ is y odd? | |
| addnes r0, r0, r2 @ add and set flags if y is odd | |
| tst r4, #1 @ previous add may have changed flags | |
| adcne r1, r1, r3 @ add and use carry flag if y is odd | |
| lsls r2, r2, #1 @ shift lsw of x left into carry bit | |
| lsl r3, r3, #1 @ make room for the carry bit is msw | |
| adc r3, r3, #0 @ add carry bit to msw of x | |
| lsrs r4, r4, #1 @ shift y right | |
| bne loop @ if y==0, we are done | |
| str r0, [r6, #8] @ store result | |