[libunwind] NFC: Use macros to accommodate differences in representation of PowerPC assemblers

[xingxue]

Summary

This NFC patch replaces the representation of registers and the left shift operator in the PowerPC assembly code to allow it to be consumed by the GNU flavored assembler and the AIX assembler.

• Registers - change the representation of PowperPC registers from %rn, %fn, %vsn, and %vrn to the register number alone, e.g., n. The GNU flavored assembler and the AIX assembler are able to determine the register kind based on the context of the instruction in which the register is used.
• Left shift operator - use macro PPC_LEFT_SHIFT to represent the left shift operator. The left shift operator in the AIX assembly language is < instead of <<

[sfertile]

Thanks for splitting this out Xing. I suggest showing the syntax differences between gas and AIX assembly we intend to work around with these macros in the commit message. LGTM.

[compnerd]

While I think that this is fine in general, I'm not sure why the shift operator needs to be replaced. Could you shed some light on that?

[MaskRay]

libunwind/src/assembly.h

220

unneeded // clang-format off ?

[xingxue]

In D101179#2721113, @compnerd wrote:

While I think that this is fine in general, I'm not sure why the shift operator needs to be replaced. Could you shed some light on that?

Sorry, I should have mentioned in the description, the left shift operator in the AIX assembly language is < instead of <<.

libunwind/src/assembly.h

220

The pre-merge check failed because clang-format wants to make the following change. However, the assembler will fail if a space is inserted in between % and the register character after it. // clang-format off is used to turn off clang-format for this segment.

clang-format: please reformat the code

-#define GPR(num) %r##num
-#define FPR(num) %f##num
-#define VSR(num) %vs##num
-#define VR(num) %v##num
+#define GPR(num) % r##num
+#define FPR(num) % f##num
+#define VSR(num) % vs##num
+#define VR(num) % v##num

[xingxue]

Hi @MaskRay @compnerd, Do you have any further comments?

[MaskRay]

Do we need GPR? ld 0, 4(3) works as ld r0, 4(r3) in GNU flavored assembly. Other macros may be similar.

[xingxue]

Addressed comments:

• Changed the representation of PowperPC registers from %rn, %fn, %vsn, and %vrn to the register number alone. The GNU flavored assembler and the AIX assembler can determine the register kind based on the context of the instruction in which the register is used.

[xingxue]

In D101179#2736893, @MaskRay wrote:

Do we need GPR? ld 0, 4(3) works as ld r0, 4(r3) in GNU flavored assembly. Other macros may be similar.

Good to know, changed according. Thanks!

[xingxue]

Minor change from clang-format.

[MaskRay]

LGTM.

libunwind/src/UnwindRegistersRestore.S

 // void libunwind::Registers_ppc64::jumpto()
 //
 // On entry:
 //  thread_state pointer is in r3
 //
 
 // load register (GPR)
 #define PPC64_LR(n) \
-  ld    %r##n, (8 * (n + 2))(%r3)
+  ld    n, (8 * (n + 2))(3)
 
   // restore integral registers
   // skip r0 for now
   // skip r1 for now
   PPC64_LR(2)
   // skip r3 for now
   // skip r4 for now
   // skip r5 for now
#define PPC64_LR(n) \
   PPC64_LR(31)
 
 #if defined(__VSX__)
 
   // restore VS registers
   // (note that this also restores floating point registers and V registers,
   // because part of VS is mapped to these registers)
 
-  addi  %r4, %r3, PPC64_OFFS_FP
+  addi  4, 3, PPC64_OFFS_FP
 
 // load VS register
 #define PPC64_LVS(n)         \
-  lxvd2x  %vs##n, 0, %r4    ;\
-  addi    %r4, %r4, 16
+  lxvd2x  n, 0, 4           ;\
+  addi    4, 4, 16
 
   // restore the first 32 VS regs (and also all floating point regs)
   PPC64_LVS(0)
   PPC64_LVS(1)
   PPC64_LVS(2)
   PPC64_LVS(3)
   PPC64_LVS(4)
   PPC64_LVS(5)
#define PPC64_LVS(n)         \
   PPC64_LVS(28)
   PPC64_LVS(29)
   PPC64_LVS(30)
   PPC64_LVS(31)
 
   // use VRSAVE to conditionally restore the remaining VS regs,
   // that are where the V regs are mapped
 
-  ld    %r5, PPC64_OFFS_VRSAVE(%r3)   // test VRsave
-  cmpwi %r5, 0
+  ld    5, PPC64_OFFS_VRSAVE(3)   // test VRsave
+  cmpwi 5, 0
   beq   Lnovec
 
 // conditionally load VS
 #define PPC64_CLVS_BOTTOM(n)               \
   beq    Ldone##n                         ;\
-  addi   %r4, %r3, PPC64_OFFS_FP + n * 16 ;\
-  lxvd2x %vs##n, 0, %r4                   ;\
+  addi   4, 3, PPC64_OFFS_FP + n * 16     ;\
+  lxvd2x n, 0, 4                          ;\
 Ldone##n:
 
-#define PPC64_CLVSl(n)           \
-  andis. %r0, %r5, (1<<(47-n))  ;\
+#define PPC64_CLVSl(n)                    \
+  andis. 0, 5, (1 PPC_LEFT_SHIFT(47-n))  ;\
 PPC64_CLVS_BOTTOM(n)
 
-#define PPC64_CLVSh(n)           \
-  andi.  %r0, %r5, (1<<(63-n))  ;\
+#define PPC64_CLVSh(n)                    \
+  andi.  0, 5, (1 PPC_LEFT_SHIFT(63-n))  ;\
 PPC64_CLVS_BOTTOM(n)
 
   PPC64_CLVSl(32)
   PPC64_CLVSl(33)
   PPC64_CLVSl(34)
   PPC64_CLVSl(35)
   PPC64_CLVSl(36)
   PPC64_CLVSl(37)
PPC64_CLVS_BOTTOM(n)
   PPC64_CLVSh(61)
   PPC64_CLVSh(62)
   PPC64_CLVSh(63)
 
 #else
 
 // load FP register
 #define PPC64_LF(n) \
-  lfd   %f##n, (PPC64_OFFS_FP + n * 16)(%r3)
+  lfd   n, (PPC64_OFFS_FP + n * 16)(3)
 
   // restore float registers
   PPC64_LF(0)
   PPC64_LF(1)
   PPC64_LF(2)
   PPC64_LF(3)
   PPC64_LF(4)
   PPC64_LF(5)
#define PPC64_LF(n) \
   PPC64_LF(27)
   PPC64_LF(28)
   PPC64_LF(29)
   PPC64_LF(30)
   PPC64_LF(31)
 
 #if defined(__ALTIVEC__)
   // restore vector registers if any are in use
-  ld    %r5, PPC64_OFFS_VRSAVE(%r3)   // test VRsave
-  cmpwi %r5, 0
+  ld    5, PPC64_OFFS_VRSAVE(3)   // test VRsave
+  cmpwi 5, 0
   beq   Lnovec
 
-  subi  %r4, %r1, 16
+  subi  4, 1, 16
   // r4 is now a 16-byte aligned pointer into the red zone
   // the _vectorScalarRegisters may not be 16-byte aligned
   // so copy via red zone temp buffer
 
 #define PPC64_CLV_UNALIGNED_BOTTOM(n)            \
   beq    Ldone##n                               ;\
-  ld     %r0, (PPC64_OFFS_V + n * 16)(%r3)      ;\
-  std    %r0, 0(%r4)                            ;\
-  ld     %r0, (PPC64_OFFS_V + n * 16 + 8)(%r3)  ;\
-  std    %r0, 8(%r4)                            ;\
-  lvx    %v##n, 0, %r4                          ;\
+  ld     0, (PPC64_OFFS_V + n * 16)(3)          ;\
+  std    0, 0(4)                                ;\
+  ld     0, (PPC64_OFFS_V + n * 16 + 8)(3)      ;\
+  std    0, 8(4)                                ;\
+  lvx    n, 0, 4                                ;\
 Ldone  ## n:
 
-#define PPC64_CLV_UNALIGNEDl(n)  \
-  andis. %r0, %r5, (1<<(15-n))  ;\
+#define PPC64_CLV_UNALIGNEDl(n)                 \
+  andis. 0, 5, (1 PPC_LEFT_SHIFT(15-n))        ;\
 PPC64_CLV_UNALIGNED_BOTTOM(n)
 
-#define PPC64_CLV_UNALIGNEDh(n)  \
-  andi.  %r0, %r5, (1<<(31-n))  ;\
+#define PPC64_CLV_UNALIGNEDh(n)                \
+  andi.  0, 5, (1 PPC_LEFT_SHIFT(31-n))       ;\
 PPC64_CLV_UNALIGNED_BOTTOM(n)
 
   PPC64_CLV_UNALIGNEDl(0)
   PPC64_CLV_UNALIGNEDl(1)
   PPC64_CLV_UNALIGNEDl(2)
   PPC64_CLV_UNALIGNEDl(3)
   PPC64_CLV_UNALIGNEDl(4)
   PPC64_CLV_UNALIGNEDl(5)
PPC64_CLV_UNALIGNED_BOTTOM(n)
   PPC64_CLV_UNALIGNEDh(29)
   PPC64_CLV_UNALIGNEDh(30)
   PPC64_CLV_UNALIGNEDh(31)
 
 #endif
 #endif
 
 Lnovec:
-  ld    %r0, PPC64_OFFS_CR(%r3)
-  mtcr  %r0
-  ld    %r0, PPC64_OFFS_SRR0(%r3)
-  mtctr %r0
+  ld    0, PPC64_OFFS_CR(3)
+  mtcr  0
+  ld    0, PPC64_OFFS_SRR0(3)
+  mtctr 0
 
   PPC64_LR(0)
   PPC64_LR(5)
   PPC64_LR(4)
   PPC64_LR(1)
   PPC64_LR(3)
   bctr
 
 #elif defined(__ppc__)
 
 DEFINE_LIBUNWIND_FUNCTION(_ZN9libunwind13Registers_ppc6jumptoEv)
 //
 // void libunwind::Registers_ppc::jumpto()
 //
 // On entry:
 //  thread_state pointer is in r3
 //
 
   // restore integral registerrs
   // skip r0 for now
   // skip r1 for now
-  lwz     %r2,  16(%r3)
+  lwz     2,  16(3)
   // skip r3 for now
   // skip r4 for now
   // skip r5 for now
-  lwz     %r6,  32(%r3)
-  lwz     %r7,  36(%r3)
-  lwz     %r8,  40(%r3)
-  lwz     %r9,  44(%r3)
-  lwz     %r10, 48(%r3)
-  lwz     %r11, 52(%r3)
-  lwz     %r12, 56(%r3)
-  lwz     %r13, 60(%r3)
-  lwz     %r14, 64(%r3)
-  lwz     %r15, 68(%r3)
-  lwz     %r16, 72(%r3)
-  lwz     %r17, 76(%r3)
-  lwz     %r18, 80(%r3)
-  lwz     %r19, 84(%r3)
-  lwz     %r20, 88(%r3)
-  lwz     %r21, 92(%r3)
-  lwz     %r22, 96(%r3)
-  lwz     %r23,100(%r3)
-  lwz     %r24,104(%r3)
-  lwz     %r25,108(%r3)
-  lwz     %r26,112(%r3)
-  lwz     %r27,116(%r3)
-  lwz     %r28,120(%r3)
-  lwz     %r29,124(%r3)
-  lwz     %r30,128(%r3)
-  lwz     %r31,132(%r3)
+  lwz     6,  32(3)
+  lwz     7,  36(3)
+  lwz     8,  40(3)
+  lwz     9,  44(3)
+  lwz     10, 48(3)
+  lwz     11, 52(3)
+  lwz     12, 56(3)
+  lwz     13, 60(3)
+  lwz     14, 64(3)
+  lwz     15, 68(3)
+  lwz     16, 72(3)
+  lwz     17, 76(3)
+  lwz     18, 80(3)
+  lwz     19, 84(3)
+  lwz     20, 88(3)
+  lwz     21, 92(3)
+  lwz     22, 96(3)
+  lwz     23,100(3)
+  lwz     24,104(3)
+  lwz     25,108(3)
+  lwz     26,112(3)
+  lwz     27,116(3)
+  lwz     28,120(3)
+  lwz     29,124(3)
+  lwz     30,128(3)
+  lwz     31,132(3)
 
 #ifndef __NO_FPRS__
   // restore float registers
-  lfd     %f0, 160(%r3)
-  lfd     %f1, 168(%r3)
-  lfd     %f2, 176(%r3)
-  lfd     %f3, 184(%r3)
-  lfd     %f4, 192(%r3)
-  lfd     %f5, 200(%r3)
-  lfd     %f6, 208(%r3)
-  lfd     %f7, 216(%r3)
-  lfd     %f8, 224(%r3)
-  lfd     %f9, 232(%r3)
-  lfd     %f10,240(%r3)
-  lfd     %f11,248(%r3)
-  lfd     %f12,256(%r3)
-  lfd     %f13,264(%r3)
-  lfd     %f14,272(%r3)
-  lfd     %f15,280(%r3)
-  lfd     %f16,288(%r3)
-  lfd     %f17,296(%r3)
-  lfd     %f18,304(%r3)
-  lfd     %f19,312(%r3)
-  lfd     %f20,320(%r3)
-  lfd     %f21,328(%r3)
-  lfd     %f22,336(%r3)
-  lfd     %f23,344(%r3)
-  lfd     %f24,352(%r3)
-  lfd     %f25,360(%r3)
-  lfd     %f26,368(%r3)
-  lfd     %f27,376(%r3)
-  lfd     %f28,384(%r3)
-  lfd     %f29,392(%r3)
-  lfd     %f30,400(%r3)
-  lfd     %f31,408(%r3)
+  lfd     0, 160(3)
+  lfd     1, 168(3)
+  lfd     2, 176(3)
+  lfd     3, 184(3)
+  lfd     4, 192(3)
+  lfd     5, 200(3)
+  lfd     6, 208(3)
+  lfd     7, 216(3)
+  lfd     8, 224(3)
+  lfd     9, 232(3)
+  lfd     10,240(3)
+  lfd     11,248(3)
+  lfd     12,256(3)
+  lfd     13,264(3)
+  lfd     14,272(3)
+  lfd     15,280(3)
+  lfd     16,288(3)
+  lfd     17,296(3)
+  lfd     18,304(3)
+  lfd     19,312(3)
+  lfd     20,320(3)
+  lfd     21,328(3)
+  lfd     22,336(3)
+  lfd     23,344(3)
+  lfd     24,352(3)
+  lfd     25,360(3)
+  lfd     26,368(3)
+  lfd     27,376(3)
+  lfd     28,384(3)
+  lfd     29,392(3)
+  lfd     30,400(3)
+  lfd     31,408(3)
 #endif
 
 #if defined(__ALTIVEC__)
   // restore vector registers if any are in use
-  lwz     %r5, 156(%r3)       // test VRsave
-  cmpwi   %r5, 0
+  lwz     5, 156(3)       // test VRsave
+  cmpwi   5, 0
   beq     Lnovec
 
-  subi    %r4, %r1, 16
-  rlwinm  %r4, %r4, 0, 0, 27  // mask low 4-bits
+  subi    4, 1, 16
+  rlwinm  4, 4, 0, 0, 27  // mask low 4-bits
   // r4 is now a 16-byte aligned pointer into the red zone
   // the _vectorRegisters may not be 16-byte aligned so copy via red zone temp buffer
- 
 
-#define LOAD_VECTOR_UNALIGNEDl(_index) \
-  andis.  %r0, %r5, (1<<(15-_index))  SEPARATOR \
+#define LOAD_VECTOR_UNALIGNEDl(_index)          \
+  andis.  0, 5, (1 PPC_LEFT_SHIFT(15-_index)) SEPARATOR \
   beq     Ldone ## _index             SEPARATOR \
-  lwz     %r0, 424+_index*16(%r3)     SEPARATOR \
-  stw     %r0, 0(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+4(%r3)   SEPARATOR \
-  stw     %r0, 4(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+8(%r3)   SEPARATOR \
-  stw     %r0, 8(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+12(%r3)  SEPARATOR \
-  stw     %r0, 12(%r4)                SEPARATOR \
-  lvx     %v ## _index, 0, %r4        SEPARATOR \
+  lwz     0, 424+_index*16(3)         SEPARATOR \
+  stw     0, 0(%r4)                   SEPARATOR \
+  lwz     0, 424+_index*16+4(%r3)     SEPARATOR \
+  stw     0, 4(%r4)                   SEPARATOR \
+  lwz     0, 424+_index*16+8(%r3)     SEPARATOR \
+  stw     0, 8(%r4)                   SEPARATOR \
+  lwz     0, 424+_index*16+12(%r3)    SEPARATOR \
+  stw     0, 12(%r4)                  SEPARATOR \
+  lvx     _index, 0, 4                SEPARATOR \
   Ldone ## _index:
 
-#define LOAD_VECTOR_UNALIGNEDh(_index) \
-  andi.   %r0, %r5, (1<<(31-_index))  SEPARATOR \
+#define LOAD_VECTOR_UNALIGNEDh(_index)          \
+  andi.   0, 5, (1<<(31-_index))      SEPARATOR \
   beq     Ldone ## _index             SEPARATOR \
-  lwz     %r0, 424+_index*16(%r3)     SEPARATOR \
-  stw     %r0, 0(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+4(%r3)   SEPARATOR \
-  stw     %r0, 4(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+8(%r3)   SEPARATOR \
-  stw     %r0, 8(%r4)                 SEPARATOR \
-  lwz     %r0, 424+_index*16+12(%r3)  SEPARATOR \
-  stw     %r0, 12(%r4)                SEPARATOR \
-  lvx     %v ## _index, 0, %r4        SEPARATOR \
+  lwz     0, 424+_index*16(3)         SEPARATOR \
+  stw     0, 0(4)                     SEPARATOR \
+  lwz     0, 424+_index*16+4(3)       SEPARATOR \
+  stw     0, 4(4)                     SEPARATOR \
+  lwz     0, 424+_index*16+8(3)       SEPARATOR \
+  stw     0, 8(%r4)                   SEPARATOR \
+  lwz     0, 424+_index*16+12(3)      SEPARATOR \
+  stw     0, 12(4)                    SEPARATOR \
+  lvx     _index, 0, 4                SEPARATOR \
   Ldone ## _index:
 
 
   LOAD_VECTOR_UNALIGNEDl(0)
   LOAD_VECTOR_UNALIGNEDl(1)
   LOAD_VECTOR_UNALIGNEDl(2)
   LOAD_VECTOR_UNALIGNEDl(3)
   LOAD_VECTOR_UNALIGNEDl(4)
#define LOAD_VECTOR_UNALIGNEDh(_index)          \
   LOAD_VECTOR_UNALIGNEDh(27)
   LOAD_VECTOR_UNALIGNEDh(28)
   LOAD_VECTOR_UNALIGNEDh(29)
   LOAD_VECTOR_UNALIGNEDh(30)
   LOAD_VECTOR_UNALIGNEDh(31)
 #endif
 
 Lnovec:
-  lwz     %r0, 136(%r3)   // __cr
-  mtcr    %r0
-  lwz     %r0, 148(%r3)   // __ctr
-  mtctr   %r0
-  lwz     %r0,   0(%r3)   // __ssr0
-  mtctr   %r0
-  lwz     %r0,   8(%r3)   // do r0 now
-  lwz     %r5,  28(%r3)   // do r5 now
-  lwz     %r4,  24(%r3)   // do r4 now
-  lwz     %r1,  12(%r3)   // do sp now
-  lwz     %r3,  20(%r3)   // do r3 last
+  lwz     0, 136(3)   // __cr
+  mtcr    0
+  lwz     0, 148(3)   // __ctr
+  mtctr   0
+  lwz     0,   0(3)   // __ssr0
+  mtctr   0
+  lwz     0,   8(3)   // do r0 now
+  lwz     5,  28(3)   // do r5 now
+  lwz     4,  24(3)   // do r4 now
+  lwz     1,  12(3)   // do sp now
+  lwz     3,  20(3)   // do r3 last
   bctr
 
 #elif defined(__aarch64__)
 
 //
 // extern "C" void __libunwind_Registers_arm64_jumpto(Registers_arm64 *);
 //
 // On entry:

libunwind/src/UnwindRegistersSave.S

 //
 // On entry:
 //  thread_state pointer is in r3
 //
 DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
 
 // store register (GPR)
 #define PPC64_STR(n) \
-  std   %r##n, (8 * (n + 2))(%r3)
+  std   n, (8 * (n + 2))(3)
 
   // save GPRs
   PPC64_STR(0)
-  mflr  %r0
-  std   %r0, PPC64_OFFS_SRR0(%r3) // store lr as ssr0
+  mflr  0
+  std   0, PPC64_OFFS_SRR0(3) // store lr as ssr0
   PPC64_STR(1)
   PPC64_STR(2)
   PPC64_STR(3)
   PPC64_STR(4)
   PPC64_STR(5)
   PPC64_STR(6)
   PPC64_STR(7)
   PPC64_STR(8)
#define PPC64_STR(n) \
   PPC64_STR(25)
   PPC64_STR(26)
   PPC64_STR(27)
   PPC64_STR(28)
   PPC64_STR(29)
   PPC64_STR(30)
   PPC64_STR(31)
 
-  mfcr  %r0
-  std   %r0,  PPC64_OFFS_CR(%r3)
-  mfxer %r0
-  std   %r0,  PPC64_OFFS_XER(%r3)
-  mflr  %r0
-  std   %r0,  PPC64_OFFS_LR(%r3)
-  mfctr %r0
-  std   %r0,  PPC64_OFFS_CTR(%r3)
-  mfvrsave    %r0
-  std   %r0,  PPC64_OFFS_VRSAVE(%r3)
+  mfcr  0
+  std   0,  PPC64_OFFS_CR(3)
+  mfxer 0
+  std   0,  PPC64_OFFS_XER(3)
+  mflr  0
+  std   0,  PPC64_OFFS_LR(3)
+  mfctr 0
+  std   0,  PPC64_OFFS_CTR(3)
+  mfvrsave    0
+  std   0,  PPC64_OFFS_VRSAVE(3)
 
 #if defined(__VSX__)
   // save VS registers
   // (note that this also saves floating point registers and V registers,
   // because part of VS is mapped to these registers)
 
-  addi  %r4, %r3, PPC64_OFFS_FP
+  addi  4, 3, PPC64_OFFS_FP
 
 // store VS register
 #define PPC64_STVS(n)      \
-  stxvd2x %vs##n, 0, %r4  ;\
-  addi    %r4, %r4, 16
+  stxvd2x n, 0, 4         ;\
+  addi    4, 4, 16
 
   PPC64_STVS(0)
   PPC64_STVS(1)
   PPC64_STVS(2)
   PPC64_STVS(3)
   PPC64_STVS(4)
   PPC64_STVS(5)
   PPC64_STVS(6)
#define PPC64_STVS(n)      \
   PPC64_STVS(61)
   PPC64_STVS(62)
   PPC64_STVS(63)
 
 #else
 
 // store FP register
 #define PPC64_STF(n) \
-  stfd  %f##n, (PPC64_OFFS_FP + n * 16)(%r3)
+  stfd  n, (PPC64_OFFS_FP + n * 16)(3)
 
   // save float registers
   PPC64_STF(0)
   PPC64_STF(1)
   PPC64_STF(2)
   PPC64_STF(3)
   PPC64_STF(4)
   PPC64_STF(5)
#define PPC64_STF(n) \
   PPC64_STF(31)
 
 #if defined(__ALTIVEC__)
   // save vector registers
 
   // Use 16-bytes below the stack pointer as an
   // aligned buffer to save each vector register.
   // Note that the stack pointer is always 16-byte aligned.
-  subi  %r4, %r1, 16
+  subi  4, 1, 16
 
-#define PPC64_STV_UNALIGNED(n)                 \
-  stvx  %v##n, 0, %r4                         ;\
-  ld    %r5, 0(%r4)                           ;\
-  std   %r5, (PPC64_OFFS_V + n * 16)(%r3)     ;\
-  ld    %r5, 8(%r4)                           ;\
-  std   %r5, (PPC64_OFFS_V + n * 16 + 8)(%r3)
+#define PPC64_STV_UNALIGNED(n)             \
+  stvx  n, 0, 4                           ;\
+  ld    5, 0(4)                           ;\
+  std   5, (PPC64_OFFS_V + n * 16)(3)     ;\
+  ld    5, 8(4)                           ;\
+  std   5, (PPC64_OFFS_V + n * 16 + 8)(3)
 
   PPC64_STV_UNALIGNED(0)
   PPC64_STV_UNALIGNED(1)
   PPC64_STV_UNALIGNED(2)
   PPC64_STV_UNALIGNED(3)
   PPC64_STV_UNALIGNED(4)
   PPC64_STV_UNALIGNED(5)
   PPC64_STV_UNALIGNED(6)
#define PPC64_STV_UNALIGNED(n)             \
   PPC64_STV_UNALIGNED(28)
   PPC64_STV_UNALIGNED(29)
   PPC64_STV_UNALIGNED(30)
   PPC64_STV_UNALIGNED(31)
 
 #endif
 #endif
 
-  li    %r3,  0   // return UNW_ESUCCESS
+  li    3,  0   // return UNW_ESUCCESS
   blr
 
 
 #elif defined(__ppc__)
 
 //
 // extern int unw_getcontext(unw_context_t* thread_state)
 //
 // On entry:
 //  thread_state pointer is in r3
 //
 DEFINE_LIBUNWIND_FUNCTION(__unw_getcontext)
-  stw     %r0,   8(%r3)
-  mflr    %r0
-  stw     %r0,   0(%r3) // store lr as ssr0
-  stw     %r1,  12(%r3)
-  stw     %r2,  16(%r3)
-  stw     %r3,  20(%r3)
-  stw     %r4,  24(%r3)
-  stw     %r5,  28(%r3)
-  stw     %r6,  32(%r3)
-  stw     %r7,  36(%r3)
-  stw     %r8,  40(%r3)
-  stw     %r9,  44(%r3)
-  stw     %r10, 48(%r3)
-  stw     %r11, 52(%r3)
-  stw     %r12, 56(%r3)
-  stw     %r13, 60(%r3)
-  stw     %r14, 64(%r3)
-  stw     %r15, 68(%r3)
-  stw     %r16, 72(%r3)
-  stw     %r17, 76(%r3)
-  stw     %r18, 80(%r3)
-  stw     %r19, 84(%r3)
-  stw     %r20, 88(%r3)
-  stw     %r21, 92(%r3)
-  stw     %r22, 96(%r3)
-  stw     %r23,100(%r3)
-  stw     %r24,104(%r3)
-  stw     %r25,108(%r3)
-  stw     %r26,112(%r3)
-  stw     %r27,116(%r3)
-  stw     %r28,120(%r3)
-  stw     %r29,124(%r3)
-  stw     %r30,128(%r3)
-  stw     %r31,132(%r3)
+  stw     0,   8(3)
+  mflr    0
+  stw     0,   0(3) // store lr as ssr0
+  stw     1,  12(3)
+  stw     2,  16(3)
+  stw     3,  20(3)
+  stw     4,  24(3)
+  stw     5,  28(3)
+  stw     6,  32(3)
+  stw     7,  36(3)
+  stw     8,  40(3)
+  stw     9,  44(3)
+  stw     10, 48(3)
+  stw     11, 52(3)
+  stw     12, 56(3)
+  stw     13, 60(3)
+  stw     14, 64(3)
+  stw     15, 68(3)
+  stw     16, 72(3)
+  stw     17, 76(3)
+  stw     18, 80(3)
+  stw     19, 84(3)
+  stw     20, 88(3)
+  stw     21, 92(3)
+  stw     22, 96(3)
+  stw     23,100(3)
+  stw     24,104(3)
+  stw     25,108(3)
+  stw     26,112(3)
+  stw     27,116(3)
+  stw     28,120(3)
+  stw     29,124(3)
+  stw     30,128(3)
+  stw     31,132(3)
 
   // save VRSave register
-  mfspr   %r0, 256
-  stw     %r0, 156(%r3)
+  mfspr   0, 256
+  stw     0, 156(3)
   // save CR registers
-  mfcr    %r0
-  stw     %r0, 136(%r3)
+  mfcr    0
+  stw     0, 136(3)
   // save CTR register
-  mfctr   %r0
-  stw     %r0, 148(%r3)
+  mfctr   0
+  stw     0, 148(3)
 
 #if !defined(__NO_FPRS__)
   // save float registers
-  stfd    %f0, 160(%r3)
-  stfd    %f1, 168(%r3)
-  stfd    %f2, 176(%r3)
-  stfd    %f3, 184(%r3)
-  stfd    %f4, 192(%r3)
-  stfd    %f5, 200(%r3)
-  stfd    %f6, 208(%r3)
-  stfd    %f7, 216(%r3)
-  stfd    %f8, 224(%r3)
-  stfd    %f9, 232(%r3)
-  stfd    %f10,240(%r3)
-  stfd    %f11,248(%r3)
-  stfd    %f12,256(%r3)
-  stfd    %f13,264(%r3)
-  stfd    %f14,272(%r3)
-  stfd    %f15,280(%r3)
-  stfd    %f16,288(%r3)
-  stfd    %f17,296(%r3)
-  stfd    %f18,304(%r3)
-  stfd    %f19,312(%r3)
-  stfd    %f20,320(%r3)
-  stfd    %f21,328(%r3)
-  stfd    %f22,336(%r3)
-  stfd    %f23,344(%r3)
-  stfd    %f24,352(%r3)
-  stfd    %f25,360(%r3)
-  stfd    %f26,368(%r3)
-  stfd    %f27,376(%r3)
-  stfd    %f28,384(%r3)
-  stfd    %f29,392(%r3)
-  stfd    %f30,400(%r3)
-  stfd    %f31,408(%r3)
+  stfd    0, 160(3)
+  stfd    1, 168(3)
+  stfd    2, 176(3)
+  stfd    3, 184(3)
+  stfd    4, 192(3)
+  stfd    5, 200(3)
+  stfd    6, 208(3)
+  stfd    7, 216(3)
+  stfd    8, 224(3)
+  stfd    9, 232(3)
+  stfd    10,240(3)
+  stfd    11,248(3)
+  stfd    12,256(3)
+  stfd    13,264(3)
+  stfd    14,272(3)
+  stfd    15,280(3)
+  stfd    16,288(3)
+  stfd    17,296(3)
+  stfd    18,304(3)
+  stfd    19,312(3)
+  stfd    20,320(3)
+  stfd    21,328(3)
+  stfd    22,336(3)
+  stfd    23,344(3)
+  stfd    24,352(3)
+  stfd    25,360(3)
+  stfd    26,368(3)
+  stfd    27,376(3)
+  stfd    28,384(3)
+  stfd    29,392(3)
+  stfd    30,400(3)
+  stfd    31,408(3)
 #endif
 
 #if defined(__ALTIVEC__)
   // save vector registers
 
-  subi    %r4, %r1, 16
-  rlwinm  %r4, %r4, 0, 0, 27  // mask low 4-bits
+  subi    4, 1, 16
+  rlwinm  4, 4, 0, 0, 27  // mask low 4-bits
   // r4 is now a 16-byte aligned pointer into the red zone
 
 #define SAVE_VECTOR_UNALIGNED(_vec, _offset) \
-  stvx    _vec, 0, %r4          SEPARATOR \
-  lwz     %r5, 0(%r4)           SEPARATOR \
-  stw     %r5, _offset(%r3)     SEPARATOR \
-  lwz     %r5, 4(%r4)           SEPARATOR \
-  stw     %r5, _offset+4(%r3)   SEPARATOR \
-  lwz     %r5, 8(%r4)           SEPARATOR \
-  stw     %r5, _offset+8(%r3)   SEPARATOR \
-  lwz     %r5, 12(%r4)          SEPARATOR \
-  stw     %r5, _offset+12(%r3)
-
-  SAVE_VECTOR_UNALIGNED( %v0, 424+0x000)
-  SAVE_VECTOR_UNALIGNED( %v1, 424+0x010)
-  SAVE_VECTOR_UNALIGNED( %v2, 424+0x020)
-  SAVE_VECTOR_UNALIGNED( %v3, 424+0x030)
-  SAVE_VECTOR_UNALIGNED( %v4, 424+0x040)
-  SAVE_VECTOR_UNALIGNED( %v5, 424+0x050)
-  SAVE_VECTOR_UNALIGNED( %v6, 424+0x060)
-  SAVE_VECTOR_UNALIGNED( %v7, 424+0x070)
-  SAVE_VECTOR_UNALIGNED( %v8, 424+0x080)
-  SAVE_VECTOR_UNALIGNED( %v9, 424+0x090)
-  SAVE_VECTOR_UNALIGNED(%v10, 424+0x0A0)
-  SAVE_VECTOR_UNALIGNED(%v11, 424+0x0B0)
-  SAVE_VECTOR_UNALIGNED(%v12, 424+0x0C0)
-  SAVE_VECTOR_UNALIGNED(%v13, 424+0x0D0)
-  SAVE_VECTOR_UNALIGNED(%v14, 424+0x0E0)
-  SAVE_VECTOR_UNALIGNED(%v15, 424+0x0F0)
-  SAVE_VECTOR_UNALIGNED(%v16, 424+0x100)
-  SAVE_VECTOR_UNALIGNED(%v17, 424+0x110)
-  SAVE_VECTOR_UNALIGNED(%v18, 424+0x120)
-  SAVE_VECTOR_UNALIGNED(%v19, 424+0x130)
-  SAVE_VECTOR_UNALIGNED(%v20, 424+0x140)
-  SAVE_VECTOR_UNALIGNED(%v21, 424+0x150)
-  SAVE_VECTOR_UNALIGNED(%v22, 424+0x160)
-  SAVE_VECTOR_UNALIGNED(%v23, 424+0x170)
-  SAVE_VECTOR_UNALIGNED(%v24, 424+0x180)
-  SAVE_VECTOR_UNALIGNED(%v25, 424+0x190)
-  SAVE_VECTOR_UNALIGNED(%v26, 424+0x1A0)
-  SAVE_VECTOR_UNALIGNED(%v27, 424+0x1B0)
-  SAVE_VECTOR_UNALIGNED(%v28, 424+0x1C0)
-  SAVE_VECTOR_UNALIGNED(%v29, 424+0x1D0)
-  SAVE_VECTOR_UNALIGNED(%v30, 424+0x1E0)
-  SAVE_VECTOR_UNALIGNED(%v31, 424+0x1F0)
+  stvx    _vec, 0, 4               SEPARATOR \
+  lwz     5, 0(4)                  SEPARATOR \
+  stw     5, _offset(3)            SEPARATOR \
+  lwz     5, 4(4)                  SEPARATOR \
+  stw     5, _offset+4(3)          SEPARATOR \
+  lwz     5, 8(4)                  SEPARATOR \
+  stw     5, _offset+8(3)          SEPARATOR \
+  lwz     5, 12(4)                 SEPARATOR \
+  stw     5, _offset+12(3)
+
+  SAVE_VECTOR_UNALIGNED( 0, 424+0x000)
+  SAVE_VECTOR_UNALIGNED( 1, 424+0x010)
+  SAVE_VECTOR_UNALIGNED( 2, 424+0x020)
+  SAVE_VECTOR_UNALIGNED( 3, 424+0x030)
+  SAVE_VECTOR_UNALIGNED( 4, 424+0x040)
+  SAVE_VECTOR_UNALIGNED( 5, 424+0x050)
+  SAVE_VECTOR_UNALIGNED( 6, 424+0x060)
+  SAVE_VECTOR_UNALIGNED( 7, 424+0x070)
+  SAVE_VECTOR_UNALIGNED( 8, 424+0x080)
+  SAVE_VECTOR_UNALIGNED( 9, 424+0x090)
+  SAVE_VECTOR_UNALIGNED(10, 424+0x0A0)
+  SAVE_VECTOR_UNALIGNED(11, 424+0x0B0)
+  SAVE_VECTOR_UNALIGNED(12, 424+0x0C0)
+  SAVE_VECTOR_UNALIGNED(13, 424+0x0D0)
+  SAVE_VECTOR_UNALIGNED(14, 424+0x0E0)
+  SAVE_VECTOR_UNALIGNED(15, 424+0x0F0)
+  SAVE_VECTOR_UNALIGNED(16, 424+0x100)
+  SAVE_VECTOR_UNALIGNED(17, 424+0x110)
+  SAVE_VECTOR_UNALIGNED(18, 424+0x120)
+  SAVE_VECTOR_UNALIGNED(19, 424+0x130)
+  SAVE_VECTOR_UNALIGNED(20, 424+0x140)
+  SAVE_VECTOR_UNALIGNED(21, 424+0x150)
+  SAVE_VECTOR_UNALIGNED(22, 424+0x160)
+  SAVE_VECTOR_UNALIGNED(23, 424+0x170)
+  SAVE_VECTOR_UNALIGNED(24, 424+0x180)
+  SAVE_VECTOR_UNALIGNED(25, 424+0x190)
+  SAVE_VECTOR_UNALIGNED(26, 424+0x1A0)
+  SAVE_VECTOR_UNALIGNED(27, 424+0x1B0)
+  SAVE_VECTOR_UNALIGNED(28, 424+0x1C0)
+  SAVE_VECTOR_UNALIGNED(29, 424+0x1D0)
+  SAVE_VECTOR_UNALIGNED(30, 424+0x1E0)
+  SAVE_VECTOR_UNALIGNED(31, 424+0x1F0)
 #endif
 
-  li      %r3, 0  // return UNW_ESUCCESS
+  li      3, 0  // return UNW_ESUCCESS
   blr
 
 
 #elif defined(__aarch64__)
 
 //
 // extern int __unw_getcontext(unw_context_t* thread_state)
 //

libunwind/src/assembly.h

 
 #ifdef ARM_HAS_BX
 #define JMP(r) bx r
 #else
 #define JMP(r) mov pc, r
 #endif
 #endif /* __arm__ */
 
+#if defined(__ppc__) || defined(__powerpc64__)
+#define PPC_LEFT_SHIFT(index) <<(index)
+#endif
+
 #endif /* UNWIND_ASSEMBLY_H */