| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 1 | #include <linux/linkage.h> |
| 2 | |
| 3 | /* |
| 4 | * Multiply operation for 32 bit integers. |
| 5 | * Input : Operand1 in Reg r5 |
| 6 | * Operand2 in Reg r6 |
| 7 | * Output: Result [op1 * op2] in Reg r3 |
| 8 | */ |
| 9 | .text |
| 10 | .globl __mulsi3 |
| 11 | .type __mulsi3, @function |
| 12 | .ent __mulsi3 |
| 13 | |
| 14 | __mulsi3: |
| 15 | .frame r1, 0, r15 |
| 16 | add r3, r0, r0 |
| 17 | beqi r5, result_is_zero /* multiply by zero */ |
| 18 | beqi r6, result_is_zero /* multiply by zero */ |
| 19 | bgeid r5, r5_pos |
| 20 | xor r4, r5, r6 /* get the sign of the result */ |
| 21 | rsubi r5, r5, 0 /* make r5 positive */ |
| 22 | r5_pos: |
| 23 | bgei r6, r6_pos |
| 24 | rsubi r6, r6, 0 /* make r6 positive */ |
| 25 | r6_pos: |
| 26 | bri l1 |
| 27 | l2: |
| 28 | add r5, r5, r5 |
| 29 | l1: |
| 30 | srl r6, r6 |
| 31 | addc r7, r0, r0 |
| 32 | beqi r7, l2 |
| 33 | bneid r6, l2 |
| 34 | add r3, r3, r5 |
| 35 | blti r4, negateresult |
| 36 | rtsd r15, 8 |
| 37 | nop |
| 38 | negateresult: |
| 39 | rtsd r15, 8 |
| 40 | rsub r3, r3, r0 |
| 41 | result_is_zero: |
| 42 | rtsd r15, 8 |
| 43 | addi r3, r0, 0 |
| 44 | |
| 45 | .size __mulsi3, . - __mulsi3 |
| 46 | .end __mulsi3 |