Re: [boost] [Context] RFR: Add support for ARM aarch64 architecture

Subject: Re: [boost] [Context] RFR: Add support for ARM aarch64 architecture
From: Edward Nevill (edward.nevill_at_[hidden])
Date: 2015-02-23 12:44:15

Hi Oliver,

Thanks for looking at this so quickly. The develop branch does not build
because when I build <abi> is set to 'sysv' not 'aapcs'. I have patched it
as in the patch below by just changing <abi>aapcs to <abi>sysv in
build/Jamfile.v2. I have not changed the name of the .S files so they are
now somewhat inappropriately named *_aapcs_*.

There was also a problem with jump_fcontext in that it was restoring the FP
context from x0, not from SP. Interestingly I based my patch on the
existing iOS code which also has this bug. I have not fixed it in the iOS
code as I have no way of testing anything on iOS.

Built and testing on arm64, ubuntu 14.04, gcc 4.9.1.

Thanks for your help with this,
Ed.

--- CUT HERE ---
commit d19baee73f90de01375af69a9f8621799c649964
Author: Edward Nevill <edward.nevill_at_[hidden]>
Date:   Mon Feb 23 17:32:49 2015 +0000

    Fix build for aarch64.
    Restore FP registers from sp, not x0

diff --git a/build/Jamfile.v2 b/build/Jamfile.v2
index 4bf3fce..00ee44d 100644
--- a/build/Jamfile.v2
+++ b/build/Jamfile.v2
@@ -227,7 +227,7 @@ alias asm_context_sources
 alias asm_context_sources
    : [ make asm/make_arm64_aapcs_elf_gas.o :
asm/make_arm64_aapcs_elf_gas.S : @gas64 ]
      [ make asm/jump_arm64_aapcs_elf_gas.o :
asm/jump_arm64_aapcs_elf_gas.S : @gas64 ]
-   : <abi>aapcs
+   : <abi>sysv
      <address-model>64
      <architecture>arm
      <binary-format>elf
@@ -236,7 +236,7 @@ alias asm_context_sources
 alias asm_context_sources
    : asm/make_arm64_aapcs_elf_gas.S
      asm/jump_arm64_aapcs_elf_gas.S
-   : <abi>aapcs
+   : <abi>sysv
      <address-model>64
      <architecture>arm
      <binary-format>elf
@@ -246,7 +246,7 @@ alias asm_context_sources
 alias asm_context_sources
    : asm/make_arm64_aapcs_elf_gas.S
      asm/jump_arm64_aapcs_elf_gas.S
-   : <abi>aapcs
+   : <abi>sysv
      <address-model>64
      <architecture>arm
      <binary-format>elf
diff --git a/src/asm/jump_arm64_aapcs_elf_gas.S
b/src/asm/jump_arm64_aapcs_elf_gas.S
index 46e029d..645d84d 100644
--- a/src/asm/jump_arm64_aapcs_elf_gas.S
+++ b/src/asm/jump_arm64_aapcs_elf_gas.S
@@ -101,10 +101,10 @@ jump_fcontext:
 #    b.eq  2f

     # load d8 - d15
-    ldp    d8, d9,   [x0, #0x00]
-    ldp    d10, d11, [x0, #0x10]
-    ldp    d12, d13, [x0, #0x20]
-    ldp    d14, d15, [x0, #0x30]
+    ldp    d8, d9,   [sp, #0x00]
+    ldp    d10, d11, [sp, #0x10]
+    ldp    d12, d13, [sp, #0x20]
+    ldp    d14, d15, [sp, #0x30]

 2:
     # load x19-x30
--- CUT HERE ---

On 23 February 2015 at 15:25, Oliver Kowalke <oliver.kowalke_at_[hidden]>
wrote:

> thx for the patches - I've updated branch develop. Could you verify that
> the code is running
> on your arm64 system (if it is working I'll merge to master).
>
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