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      1 //===-- aeabi_cdcmp.S - EABI cdcmp* implementation ------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is dual licensed under the MIT and the University of Illinois Open
      6 // Source Licenses. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "../assembly.h"
     11 
     12 #if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__
     13 #error big endian support not implemented
     14 #endif
     15 
     16 #define APSR_Z (1 << 30)
     17 #define APSR_C (1 << 29)
     18 
     19 // void __aeabi_cdcmpeq(double a, double b) {
     20 //   if (isnan(a) || isnan(b)) {
     21 //     Z = 0; C = 1;
     22 //   } else {
     23 //     __aeabi_cdcmple(a, b);
     24 //   }
     25 // }
     26 
     27         .syntax unified
     28         .p2align 2
     29 DEFINE_COMPILERRT_FUNCTION(__aeabi_cdcmpeq)
     30         push {r0-r3, lr}
     31         bl __aeabi_cdcmpeq_check_nan
     32         cmp r0, #1
     33         pop {r0-r3, lr}
     34 
     35         // NaN has been ruled out, so __aeabi_cdcmple can't trap
     36         bne __aeabi_cdcmple
     37 
     38         msr CPSR_f, #APSR_C
     39         JMP(lr)
     40 END_COMPILERRT_FUNCTION(__aeabi_cdcmpeq)
     41 
     42 
     43 // void __aeabi_cdcmple(double a, double b) {
     44 //   if (__aeabi_dcmplt(a, b)) {
     45 //     Z = 0; C = 0;
     46 //   } else if (__aeabi_dcmpeq(a, b)) {
     47 //     Z = 1; C = 1;
     48 //   } else {
     49 //     Z = 0; C = 1;
     50 //   }
     51 // }
     52 
     53         .syntax unified
     54         .p2align 2
     55 DEFINE_COMPILERRT_FUNCTION(__aeabi_cdcmple)
     56         // Per the RTABI, this function must preserve r0-r11.
     57         // Save lr in the same instruction for compactness
     58         push {r0-r3, lr}
     59 
     60         bl __aeabi_dcmplt
     61         cmp r0, #1
     62         moveq ip, #0
     63         beq 1f
     64 
     65         ldm sp, {r0-r3}
     66         bl __aeabi_dcmpeq
     67         cmp r0, #1
     68         moveq ip, #(APSR_C | APSR_Z)
     69         movne ip, #(APSR_C)
     70 
     71 1:
     72         msr CPSR_f, ip
     73         pop {r0-r3}
     74         POP_PC()
     75 END_COMPILERRT_FUNCTION(__aeabi_cdcmple)
     76 
     77 // int __aeabi_cdrcmple(double a, double b) {
     78 //   return __aeabi_cdcmple(b, a);
     79 // }
     80 
     81         .syntax unified
     82         .p2align 2
     83 DEFINE_COMPILERRT_FUNCTION(__aeabi_cdrcmple)
     84         // Swap r0 and r2
     85         mov ip, r0
     86         mov r0, r2
     87         mov r2, ip
     88 
     89         // Swap r1 and r3
     90         mov ip, r1
     91         mov r1, r3
     92         mov r3, ip
     93 
     94         b __aeabi_cdcmple
     95 END_COMPILERRT_FUNCTION(__aeabi_cdrcmple)
     96 
     97 NO_EXEC_STACK_DIRECTIVE
     98 
     99