diff options
Diffstat (limited to 'arm/PrintAsm.ml')
| -rw-r--r-- | arm/PrintAsm.ml | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/arm/PrintAsm.ml b/arm/PrintAsm.ml index f1beded..c50acba 100644 --- a/arm/PrintAsm.ml +++ b/arm/PrintAsm.ml @@ -370,14 +370,50 @@ let print_builtin_vstore oc chunk args = end in fprintf oc "%s end builtin __builtin_volatile_write\n" comment; n +(* Magic sequence for byte-swapping *) + +let print_bswap oc src dst tmp = + (* tmp <> src, tmp <> dst, but can have dst = src *) + (* src = A . B .C . D *) + fprintf oc " eor %a, %a, %a, ror #16\n" ireg tmp ireg src ireg src; + (* tmp = A^C . B^D . C^A . D^B *) + fprintf oc " bic %a, %a, #0x00FF0000\n" ireg tmp ireg tmp; + (* tmp = A^C . 000 . C^A . D^B *) + fprintf oc " mov %a, %a, ror #8\n" ireg dst ireg src; + (* dst = D . A . B . C *) + fprintf oc " eor %a, %a, %a, lsr #8\n" ireg dst ireg dst ireg tmp + (* dst = D . A^A^C . B . C^C^A = D . C . B . A *) + (* Handling of compiler-inlined builtins *) let print_builtin_inline oc name args res = fprintf oc "%s begin %s\n" comment name; let n = match name, args, res with + (* Integer arithmetic *) + | "__builtin_bswap", [IR a1], IR res -> + print_bswap oc a1 IR14 res; 4 (* Float arithmetic *) | "__builtin_fabs", [FR a1], FR res -> fprintf oc " fabsd %a, %a\n" freg res freg a1; 1 + | "__builtin_fsqrt", [FR a1], FR res -> + fprintf oc " fsqrtd %a, %a\n" freg res freg a1; 1 + (* Memory accesses *) + | "__builtin_read_int16_reversed", [IR a1], IR res -> + fprintf oc " ldrh %a, [%a, #0]\n" ireg res ireg a1; + fprintf oc " mov %a, %a, lsr #8\n" ireg IR14 ireg res; + fprintf oc " orr %a, %a, %a, lsl #8\n" ireg res ireg IR14 ireg res; 3 + | "__builtin_read_int32_reversed", [IR a1], IR res -> + fprintf oc " ldr %a, [%a, #0]\n" ireg res ireg a1; + print_bswap oc res IR14 res; 5 + | "__builtin_write_int16_reversed", [IR a1; IR a2], _ -> + fprintf oc " mov %a, %a, lsr #8\n" ireg IR14 ireg a2; + fprintf oc " and %a, %a, #0xFF\n" ireg IR14 ireg IR14; + fprintf oc " orr %a, %a, %a, lsl #8\n" ireg IR14 ireg IR14 ireg a2; + fprintf oc " strh %a, [%a, #0]\n" ireg IR14 ireg a1; 4 + | "__builtin_write_int32_reversed", [IR a1; IR a2], _ -> + let tmp = if a1 = IR10 then IR12 else IR10 in + print_bswap oc a2 IR14 tmp; + fprintf oc " str %a, [%a, #0]\n" ireg tmp ireg a1; 5 (* Catch-all *) | _ -> invalid_arg ("unrecognized builtin " ^ name) |