Projects : gscm : gscm_usrbin
| 1 | .intel_syntax noprefix |
| 2 | .global sc_wide_mul |
| 3 | .global sc_wide_mul_signed |
| 4 | .global sc_bit_length |
| 5 | .global sc_div_extended |
| 6 | .text |
| 7 | |
| 8 | sc_wide_mul: /* rdi=*a, rsi=*b */ |
| 9 | mov rax, [rdi] /* *a -> rax */ |
| 10 | mul qword ptr [rsi] /* unsigned rax*(*b) -> rdx:rax */ |
| 11 | mov [rdi], rax /* lo -> *a */ |
| 12 | mov [rsi], rdx /* hi -> *b */ |
| 13 | ret |
| 14 | |
| 15 | sc_wide_mul_signed: |
| 16 | mov rax, [rdi] |
| 17 | imul qword ptr [rsi] |
| 18 | mov [rdi], rax |
| 19 | mov [rsi], rdx |
| 20 | ret |
| 21 | |
| 22 | sc_bit_length: /* rdi=a */ |
| 23 | bsr rax, rdi /* Bit Scan Reverse */ |
| 24 | jz .L1 |
| 25 | inc rax |
| 26 | ret |
| 27 | .L1: /* a=0: rax undefined */ |
| 28 | xor rax, rax |
| 29 | ret |
| 30 | |
| 31 | sc_div_extended: /* rdi=*a_lo, rsi=*a_hi, rdx=b */ |
| 32 | mov rcx, rdx /* save b -> rcx */ |
| 33 | mov rax, [rdi] /* *a_lo -> rax */ |
| 34 | mov rdx, [rsi] /* *a_hi -> rdx */ |
| 35 | div rcx /* unsigned rdx:rax / b -> Q rax, R rdx */ |
| 36 | mov [rsi], rax /* quotient -> *a_hi */ |
| 37 | mov [rdi], rdx /* remainder -> *a_lo */ |
| 38 | ret |