-06160ccaed7af7955d169024f417c43beb7a8f9f
+934df6f8cf848071dd0312098975f0c13873e01c
The first line of this file holds the git revision number of the last
merge done from the dlang/dmd repository.
+// RUNNABLE_PHOBOS_TEST
import std.math;
extern(C) int printf(const char*, ...);
+// RUNNABLE_PHOBOS_TEST
// PERMUTE_ARGS:
int magicVariable()
+// RUNNABLE_PHOBOS_TEST
// original post to the D newsgroup:
// http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=D&artnum=10554&header
// Test to manipulate 3D vectors, in D!
+// RUNNABLE_PHOBOS_TEST
// PERMUTE_ARGS:
extern(C) int printf(const char*, ...);
-476882795473a884f837bea6da850ac5181868d1
+7bdd83d7b4bd9fd4cb9ffca0d50babc90b31bfd6
The first line of this file holds the git revision number of the last
merge done from the dlang/druntime repository.
DRUNTIME_SOURCES_CONFIGURED += config/mips/switchcontext.S
endif
if DRUNTIME_CPU_POWERPC
- DRUNTIME_SOURCES_CONFIGURED += config/powerpc/callwithstack.S \
- config/powerpc/switchcontext.S
+ DRUNTIME_SOURCES_CONFIGURED += config/powerpc/switchcontext.S
endif
if DRUNTIME_CPU_X86
if DRUNTIME_OS_MINGW
@DRUNTIME_CPU_AARCH64_TRUE@am__append_11 = config/aarch64/switchcontext.S
@DRUNTIME_CPU_ARM_TRUE@am__append_12 = config/arm/switchcontext.S
@DRUNTIME_CPU_MIPS_TRUE@am__append_13 = config/mips/switchcontext.S
-@DRUNTIME_CPU_POWERPC_TRUE@am__append_14 = config/powerpc/callwithstack.S \
-@DRUNTIME_CPU_POWERPC_TRUE@ config/powerpc/switchcontext.S
-
+@DRUNTIME_CPU_POWERPC_TRUE@am__append_14 = config/powerpc/switchcontext.S
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_TRUE@am__append_15 = config/mingw/switchcontext.S
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_FALSE@am__append_16 = config/x86/switchcontext.S
@DRUNTIME_CPU_SYSTEMZ_TRUE@am__append_17 = config/systemz/get_tls_offset.S
@DRUNTIME_CPU_AARCH64_TRUE@am__objects_23 = config/aarch64/libgdruntime_la-switchcontext.lo
@DRUNTIME_CPU_ARM_TRUE@am__objects_24 = config/arm/libgdruntime_la-switchcontext.lo
@DRUNTIME_CPU_MIPS_TRUE@am__objects_25 = config/mips/libgdruntime_la-switchcontext.lo
-@DRUNTIME_CPU_POWERPC_TRUE@am__objects_26 = config/powerpc/libgdruntime_la-callwithstack.lo \
-@DRUNTIME_CPU_POWERPC_TRUE@ config/powerpc/libgdruntime_la-switchcontext.lo
+@DRUNTIME_CPU_POWERPC_TRUE@am__objects_26 = config/powerpc/libgdruntime_la-switchcontext.lo
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_TRUE@am__objects_27 = config/mingw/libgdruntime_la-switchcontext.lo
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_FALSE@am__objects_28 = config/x86/libgdruntime_la-switchcontext.lo
@DRUNTIME_CPU_SYSTEMZ_TRUE@am__objects_29 = config/systemz/libgdruntime_la-get_tls_offset.lo
@DRUNTIME_CPU_AARCH64_TRUE@am__objects_35 = config/aarch64/libgdruntime_convenience_la-switchcontext.lo
@DRUNTIME_CPU_ARM_TRUE@am__objects_36 = config/arm/libgdruntime_convenience_la-switchcontext.lo
@DRUNTIME_CPU_MIPS_TRUE@am__objects_37 = config/mips/libgdruntime_convenience_la-switchcontext.lo
-@DRUNTIME_CPU_POWERPC_TRUE@am__objects_38 = config/powerpc/libgdruntime_convenience_la-callwithstack.lo \
-@DRUNTIME_CPU_POWERPC_TRUE@ config/powerpc/libgdruntime_convenience_la-switchcontext.lo
+@DRUNTIME_CPU_POWERPC_TRUE@am__objects_38 = config/powerpc/libgdruntime_convenience_la-switchcontext.lo
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_TRUE@am__objects_39 = config/mingw/libgdruntime_convenience_la-switchcontext.lo
@DRUNTIME_CPU_X86_TRUE@@DRUNTIME_OS_MINGW_FALSE@am__objects_40 = config/x86/libgdruntime_convenience_la-switchcontext.lo
@DRUNTIME_CPU_SYSTEMZ_TRUE@am__objects_41 = config/systemz/libgdruntime_convenience_la-get_tls_offset.lo
config/powerpc/$(am__dirstamp):
@$(MKDIR_P) config/powerpc
@: > config/powerpc/$(am__dirstamp)
-config/powerpc/libgdruntime_la-callwithstack.lo: \
- config/powerpc/$(am__dirstamp)
config/powerpc/libgdruntime_la-switchcontext.lo: \
config/powerpc/$(am__dirstamp)
config/mingw/$(am__dirstamp):
config/arm/$(am__dirstamp)
config/mips/libgdruntime_convenience_la-switchcontext.lo: \
config/mips/$(am__dirstamp)
-config/powerpc/libgdruntime_convenience_la-callwithstack.lo: \
- config/powerpc/$(am__dirstamp)
config/powerpc/libgdruntime_convenience_la-switchcontext.lo: \
config/powerpc/$(am__dirstamp)
config/mingw/libgdruntime_convenience_la-switchcontext.lo: \
config/mips/libgdruntime_la-switchcontext.lo: config/mips/switchcontext.S
$(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/mips/libgdruntime_la-switchcontext.lo `test -f 'config/mips/switchcontext.S' || echo '$(srcdir)/'`config/mips/switchcontext.S
-config/powerpc/libgdruntime_la-callwithstack.lo: config/powerpc/callwithstack.S
- $(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/powerpc/libgdruntime_la-callwithstack.lo `test -f 'config/powerpc/callwithstack.S' || echo '$(srcdir)/'`config/powerpc/callwithstack.S
-
config/powerpc/libgdruntime_la-switchcontext.lo: config/powerpc/switchcontext.S
$(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/powerpc/libgdruntime_la-switchcontext.lo `test -f 'config/powerpc/switchcontext.S' || echo '$(srcdir)/'`config/powerpc/switchcontext.S
config/mips/libgdruntime_convenience_la-switchcontext.lo: config/mips/switchcontext.S
$(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_convenience_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/mips/libgdruntime_convenience_la-switchcontext.lo `test -f 'config/mips/switchcontext.S' || echo '$(srcdir)/'`config/mips/switchcontext.S
-config/powerpc/libgdruntime_convenience_la-callwithstack.lo: config/powerpc/callwithstack.S
- $(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_convenience_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/powerpc/libgdruntime_convenience_la-callwithstack.lo `test -f 'config/powerpc/callwithstack.S' || echo '$(srcdir)/'`config/powerpc/callwithstack.S
-
config/powerpc/libgdruntime_convenience_la-switchcontext.lo: config/powerpc/switchcontext.S
$(AM_V_CPPAS)$(LIBTOOL) $(AM_V_lt) $(libgdruntime_convenience_la_LIBTOOLFLAGS) $(LIBTOOLFLAGS) --mode=compile $(CCAS) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CCASFLAGS) $(CCASFLAGS) -c -o config/powerpc/libgdruntime_convenience_la-switchcontext.lo `test -f 'config/powerpc/switchcontext.S' || echo '$(srcdir)/'`config/powerpc/switchcontext.S
+++ /dev/null
-/* PowerPC64 support code for fibers and multithreading.
- Copyright (C) 2019-2020 Free Software Foundation, Inc.
-
-This file is part of GCC.
-
-GCC is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 3, or (at your option) any later
-version.
-
-GCC is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY; without even the implied warranty of MERCHANTABILITY or
-FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-for more details.
-
-Under Section 7 of GPL version 3, you are granted additional
-permissions described in the GCC Runtime Library Exception, version
-3.1, as published by the Free Software Foundation.
-
-You should have received a copy of the GNU General Public License and
-a copy of the GCC Runtime Library Exception along with this program;
-see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
-<http://www.gnu.org/licenses/>. */
-
-#include "../common/threadasm.S"
-
-#if defined(__PPC64__)
-
-#if defined(_CALL_ELF) && _CALL_ELF == 2
-#define USE_ABI_2
-#define LINKAGE_SZ 32
-#define LR_OFS 16
-#define TOC_OFS 24
-#define GPR_OFS 32
-#define STACK_SZ (LINKAGE_SZ + 26*8)
-#define OFS_R3_R10 GPR_OFS
-#define OFS_R14_R31 (GPR_OFS+8*8)
-#else
-#define LINKAGE_SZ 48
-#define LR_OFS 16
-#define TOC_OFS 40
-#define GPR_OFS 112
-#define STACK_SZ (LINKAGE_SZ + 8*8 + 18*8)
-#define OFS_R3_R10 (STACK_SZ+LINKAGE_SZ)
-#define OFS_R14_R31 GPR_OFS
-#endif
-
- .text
-#if defined( USE_ABI_2 )
- .abiversion 2
-#endif
- .globl _D4core6thread18callWithStackShellFNbMDFNbPvZvZv
- .align 2
- .type _D4core6thread18callWithStackShellFNbMDFNbPvZvZv,@function
-#if defined( USE_ABI_2 )
- .section .text._D4core6thread18callWithStackShellFNbMDFNbPvZvZv,"a",@progbits
-#else
- .section .opd,"aw",@progbits
-#endif
-_D4core6thread18callWithStackShellFNbMDFNbPvZvZv:
-#if !defined( USE_ABI_2 )
- .align 3
- .quad .L._D4core6thread18callWithStackShellFNbMDFNbPvZvZv
- .quad .TOC.@tocbase
- .quad 0
-#endif
- .text
-/*
- * Called with:
- * r3: pointer context
- * r4: pointer to function
- */
-.L._D4core6thread18callWithStackShellFNbMDFNbPvZvZv:
- .cfi_startproc
- stdu 1, -STACK_SZ(1)
- mflr 0
- std 0, LR_OFS(1)
- .cfi_def_cfa_offset 256
- .cfi_offset lr, 16
-
- /* Save r14-r31 in general register save area */
- std 14, (OFS_R14_R31 + 0 * 8)(1)
- std 15, (OFS_R14_R31 + 1 * 8)(1)
- std 16, (OFS_R14_R31 + 2 * 8)(1)
- std 17, (OFS_R14_R31 + 3 * 8)(1)
- std 18, (OFS_R14_R31 + 4 * 8)(1)
- std 19, (OFS_R14_R31 + 5 * 8)(1)
- std 20, (OFS_R14_R31 + 6 * 8)(1)
- std 21, (OFS_R14_R31 + 7 * 8)(1)
- std 22, (OFS_R14_R31 + 8 * 8)(1)
- std 23, (OFS_R14_R31 + 9 * 8)(1)
- std 24, (OFS_R14_R31 + 10 * 8)(1)
- std 25, (OFS_R14_R31 + 11 * 8)(1)
- std 26, (OFS_R14_R31 + 12 * 8)(1)
- std 27, (OFS_R14_R31 + 13 * 8)(1)
- std 28, (OFS_R14_R31 + 14 * 8)(1)
- std 29, (OFS_R14_R31 + 15 * 8)(1)
- std 30, (OFS_R14_R31 + 16 * 8)(1)
- std 31, (OFS_R14_R31 + 17 * 8)(1)
-
- /* Save r3-r10 in parameter save area of caller */
- std 3, (OFS_R3_R10 + 0 * 8)(1)
- std 4, (OFS_R3_R10 + 1 * 8)(1)
- std 5, (OFS_R3_R10 + 2 * 8)(1)
- std 6, (OFS_R3_R10 + 3 * 8)(1)
- std 7, (OFS_R3_R10 + 4 * 8)(1)
- std 8, (OFS_R3_R10 + 5 * 8)(1)
- std 9, (OFS_R3_R10 + 6 * 8)(1)
- std 10, (OFS_R3_R10 + 7 * 8)(1)
-
- /* Save r2 in TOC save area */
- std 2, TOC_OFS(1)
-
- /* Do not save r11, r12 and r13. */
-
- /* Call delegate:
- * r3: pointer to context
- * r4: pointer to stack
- */
- mr 5, 4
- mr 4, 1
- ld 6, 0(5)
- ld 11, 16(5)
- ld 2, 8(5)
- mtctr 6
- bctrl
- nop
-
- /* Restore r2 from TOC save area */
- ld 2, TOC_OFS(1)
-
- /* Restore r3-r10 from local variable space */
- ld 3, (OFS_R3_R10 + 0 * 8)(1)
- ld 4, (OFS_R3_R10 + 1 * 8)(1)
- ld 5, (OFS_R3_R10 + 2 * 8)(1)
- ld 6, (OFS_R3_R10 + 3 * 8)(1)
- ld 7, (OFS_R3_R10 + 4 * 8)(1)
- ld 8, (OFS_R3_R10 + 5 * 8)(1)
- ld 9, (OFS_R3_R10 + 6 * 8)(1)
- ld 10, (OFS_R3_R10 + 7 * 8)(1)
-
- /* Restore r14-r31 from general register save area */
- ld 14, (OFS_R14_R31 + 0 * 8)(1)
- ld 15, (OFS_R14_R31 + 1 * 8)(1)
- ld 16, (OFS_R14_R31 + 2 * 8)(1)
- ld 17, (OFS_R14_R31 + 3 * 8)(1)
- ld 18, (OFS_R14_R31 + 4 * 8)(1)
- ld 19, (OFS_R14_R31 + 5 * 8)(1)
- ld 20, (OFS_R14_R31 + 6 * 8)(1)
- ld 21, (OFS_R14_R31 + 7 * 8)(1)
- ld 22, (OFS_R14_R31 + 8 * 8)(1)
- ld 23, (OFS_R14_R31 + 9 * 8)(1)
- ld 24, (OFS_R14_R31 + 10 * 8)(1)
- ld 25, (OFS_R14_R31 + 11 * 8)(1)
- ld 26, (OFS_R14_R31 + 12 * 8)(1)
- ld 27, (OFS_R14_R31 + 13 * 8)(1)
- ld 28, (OFS_R14_R31 + 14 * 8)(1)
- ld 29, (OFS_R14_R31 + 15 * 8)(1)
- ld 30, (OFS_R14_R31 + 16 * 8)(1)
- ld 31, (OFS_R14_R31 + 17 * 8)(1)
-
- ld 0, LR_OFS(1)
- mtlr 0
- addi 1, 1, STACK_SZ
- blr
- .long 0
- .quad 0
-.Lend:
- .size _D4core6thread18callWithStackShellFNbMDFNbPvZvZv, .Lend-.L._D4core6thread18callWithStackShellFNbMDFNbPvZvZv
- .cfi_endproc
-
-#endif /* defined(__PPC64__) */
*
*/
.text
- .globl CSYM(_fiber_switchContext)
- .type CSYM(_fiber_switchContext), @function
+ .globl CSYM(fiber_switchContext)
+ .type CSYM(fiber_switchContext), @function
.align 2
-CSYM(_fiber_switchContext):
+CSYM(fiber_switchContext):
.cfi_startproc
/* Save linkage area */
mflr 0
/* Return and switch context */
blr
.cfi_endproc
- .size CSYM(_fiber_switchContext),.-CSYM(_fiber_switchContext)
+ .size CSYM(fiber_switchContext),.-CSYM(fiber_switchContext)
#endif /* !defined(__PPC64__) */
ubyte[] buff = ctfe_alloc(T.sizeof);
enum msbSize = double.sizeof;
- double hi = toPrec!double(val);
+ static if (is(Unqual!T == ireal))
+ double hi = toPrec!double(val.im);
+ else
+ double hi = toPrec!double(val);
buff[0 .. msbSize] = toUbyte(hi)[];
if (val is cast(T)0.0 || val is cast(T)-0.0 ||
}
else
{
- double low = toPrec!double(val - hi);
+ static if (is(Unqual!T == ireal))
+ double low = toPrec!double(val.im - hi);
+ else
+ double low = toPrec!double(val - hi);
buff[msbSize .. $] = toUbyte(low)[];
}
dev_t st_rdev;
c_long[2] st_pad2;
off_t st_size;
+ c_long st_pad3;
union
{
timestruc_t st_atim;
dev_t st_rdev;
c_long[2] st_pad2;
off64_t st_size;
- c_long st_pad3;
union
{
timestruc_t st_atim;
// Used for needLock below.
private __gshared bool multiThreadedFlag = false;
-version (PPC64) version = ExternStackShell;
-
-version (ExternStackShell)
+// Calls the given delegate, passing the current thread's stack pointer to it.
+private void callWithStackShell(scope void delegate(void* sp) nothrow fn) nothrow
+in
{
- extern(D) public void callWithStackShell(scope void delegate(void* sp) nothrow fn) nothrow;
+ assert(fn);
}
-else
+body
{
- // Calls the given delegate, passing the current thread's stack pointer to it.
- private void callWithStackShell(scope void delegate(void* sp) nothrow fn) nothrow
- in
+ // The purpose of the 'shell' is to ensure all the registers get
+ // put on the stack so they'll be scanned. We only need to push
+ // the callee-save registers.
+ void *sp = void;
+
+ version (GNU)
{
- assert(fn);
+ __builtin_unwind_init();
+ sp = &sp;
}
- body
+ else version (AsmX86_Posix)
{
- // The purpose of the 'shell' is to ensure all the registers get
- // put on the stack so they'll be scanned. We only need to push
- // the callee-save registers.
- void *sp = void;
-
- version (GNU)
- {
- __builtin_unwind_init();
- sp = &sp;
- }
- else version (AsmX86_Posix)
+ size_t[3] regs = void;
+ asm pure nothrow @nogc
{
- size_t[3] regs = void;
- asm pure nothrow @nogc
- {
- mov [regs + 0 * 4], EBX;
- mov [regs + 1 * 4], ESI;
- mov [regs + 2 * 4], EDI;
+ mov [regs + 0 * 4], EBX;
+ mov [regs + 1 * 4], ESI;
+ mov [regs + 2 * 4], EDI;
- mov sp[EBP], ESP;
- }
+ mov sp[EBP], ESP;
}
- else version (AsmX86_Windows)
+ }
+ else version (AsmX86_Windows)
+ {
+ size_t[3] regs = void;
+ asm pure nothrow @nogc
{
- size_t[3] regs = void;
- asm pure nothrow @nogc
- {
- mov [regs + 0 * 4], EBX;
- mov [regs + 1 * 4], ESI;
- mov [regs + 2 * 4], EDI;
+ mov [regs + 0 * 4], EBX;
+ mov [regs + 1 * 4], ESI;
+ mov [regs + 2 * 4], EDI;
- mov sp[EBP], ESP;
- }
+ mov sp[EBP], ESP;
}
- else version (AsmX86_64_Posix)
+ }
+ else version (AsmX86_64_Posix)
+ {
+ size_t[5] regs = void;
+ asm pure nothrow @nogc
{
- size_t[5] regs = void;
- asm pure nothrow @nogc
- {
- mov [regs + 0 * 8], RBX;
- mov [regs + 1 * 8], R12;
- mov [regs + 2 * 8], R13;
- mov [regs + 3 * 8], R14;
- mov [regs + 4 * 8], R15;
+ mov [regs + 0 * 8], RBX;
+ mov [regs + 1 * 8], R12;
+ mov [regs + 2 * 8], R13;
+ mov [regs + 3 * 8], R14;
+ mov [regs + 4 * 8], R15;
- mov sp[RBP], RSP;
- }
+ mov sp[RBP], RSP;
}
- else version (AsmX86_64_Windows)
- {
- size_t[7] regs = void;
- asm pure nothrow @nogc
- {
- mov [regs + 0 * 8], RBX;
- mov [regs + 1 * 8], RSI;
- mov [regs + 2 * 8], RDI;
- mov [regs + 3 * 8], R12;
- mov [regs + 4 * 8], R13;
- mov [regs + 5 * 8], R14;
- mov [regs + 6 * 8], R15;
-
- mov sp[RBP], RSP;
- }
- }
- else
+ }
+ else version (AsmX86_64_Windows)
+ {
+ size_t[7] regs = void;
+ asm pure nothrow @nogc
{
- static assert(false, "Architecture not supported.");
- }
+ mov [regs + 0 * 8], RBX;
+ mov [regs + 1 * 8], RSI;
+ mov [regs + 2 * 8], RDI;
+ mov [regs + 3 * 8], R12;
+ mov [regs + 4 * 8], R13;
+ mov [regs + 5 * 8], R14;
+ mov [regs + 6 * 8], R15;
- fn(sp);
+ mov sp[RBP], RSP;
+ }
}
+ else
+ {
+ static assert(false, "Architecture not supported.");
+ }
+
+ fn(sp);
}
// Used for suspendAll/resumeAll below.
// Multiple threads running shared fibers
+version (PPC) version = UnsafeFiberMigration;
+version (PPC64) version = UnsafeFiberMigration;
+
+version (UnsafeFiberMigration)
+{
+ // XBUG: core.thread fibers are supposed to be safe to migrate across
+ // threads, however, there is a problem: GCC always assumes that the
+ // address of thread-local variables don't change while on a given stack.
+ // In consequence, migrating fibers between threads currently is an unsafe
+ // thing to do, and will break on some targets (possibly PR26461).
+}
+else
+{
+ version = FiberMigrationUnittest;
+}
+
+version (FiberMigrationUnittest)
unittest
{
shared bool[10] locks;
void main()
{
- auto test_fiber = new Fiber(&stackMethod, stackSize);
+ auto test_fiber = new Fiber(&stackMethod, stackSize, stackSize);
// allocate a page below (above) the fiber's stack to make stack overflows possible (w/o segfaulting)
version (StackGrowsDown)