Kernel Math Emulation again
Bill Roman
roman at alerton.com
Fri Dec 3 09:32:06 EST 1999
Neil Blackwood wrote:
>
> There is some kernel maths emulation stuff in 2.3.18.
> You will need to copy it over to which ever version you are using. It works.
> Look for directories math-emu.
> You will need to change config files and make files as well. Its fairly
> easy. Even I managed it.
Thanks, Neil! I had been very optimistic when I found this code in 2.3.18, and
was disappointed when it turned out it wouldn't compile in that context.
Without your hint, I don't think I would have guessed that transplanting it
into a 2.2 kernel would have worked.
To save everyone else a few hours of grepping and tweaking, here are
instructions and a patch file to add math emulation to the 2.2.13 kernel
sources from linuxppc.cs.nmt.edu.
1. Obtain mpc8xx-2.2.13.tgz and linux-2.3.18.tgz from
ftp://linuxppc.cs.nmt.edu/pub/linuxppc/embedded/. Untar them into two
separate source trees. (Note: all that's needed from 2.3.18 is the
math emulator; does anyone know whether that's available separately,
or could someone split it out and put it on the FTP site?)
2. Copy the arch/ppc/mathemu directory from the 2.3.18 tree to the
2.2.13 tree.
3. Apply the patch (below). Note that I am building for an MBX, so that's
what .config gets patched for.
4. make symlinks config dep clean zImage.
The following is the patch.
----------------------------------------------------------------------------
diff -ur linux-mpc8xx-2.2.13/.config linux/.config
--- linux-mpc8xx-2.2.13/.config Fri Oct 22 16:08:42 1999
+++ linux/.config Wed Dec 1 17:10:01 1999
@@ -10,9 +10,9 @@
# CONFIG_PPC64 is not set
CONFIG_8xx=y
# CONFIG_MPC821 is not set
-CONFIG_MPC823=y
+# CONFIG_MPC823 is not set
# CONFIG_MPC850 is not set
-# CONFIG_MPC860 is not set
+CONFIG_MPC860=y
# CONFIG_MPC860T is not set
CONFIG_SERIAL_CONSOLE=y
# CONFIG_PMAC is not set
@@ -20,12 +20,13 @@
# CONFIG_CHRP is not set
# CONFIG_ALL_PPC is not set
# CONFIG_APUS is not set
-# CONFIG_MBX is not set
+CONFIG_MBX=y
# CONFIG_RPXLITE is not set
# CONFIG_RPXCLASSIC is not set
-CONFIG_BSEIP=y
+# CONFIG_BSEIP is not set
# CONFIG_SMP is not set
CONFIG_MACH_SPECIFIC=y
+CONFIG_MATH_EMULATION=y
#
# General setup
@@ -297,8 +298,7 @@
# MPC8xx CPM Options
#
CONFIG_SCC_ENET=y
-# CONFIG_SCC1_ENET is not set
-CONFIG_SCC2_ENET=y
+CONFIG_SCC1_ENET=y
# CONFIG_FEC_ENET is not set
# CONFIG_CPM_IIC is not set
# CONFIG_UCODE_PATCH is not set
diff -ur linux-mpc8xx-2.2.13/arch/ppc/Makefile linux/arch/ppc/Makefile
--- linux-mpc8xx-2.2.13/arch/ppc/Makefile Wed Oct 20 15:33:30 1999
+++ linux/arch/ppc/Makefile Wed Dec 1 16:16:45 1999
@@ -41,6 +41,12 @@
ARCHIVES := arch/ppc/kernel/kernel.o arch/ppc/mm/mm.o arch/ppc/lib/lib.o $(ARCHIVES)
CORE_FILES := arch/ppc/kernel/kernel.o arch/ppc/mm/mm.o arch/ppc/lib/lib.o $(CORE_FILES)
+ifdef CONFIG_MATH_EMULATION
+SUBDIRS += arch/ppc/math-emu
+ARCHIVES += arch/ppc/math-emu/math-emu.o
+CORE_FILES += arch/ppc/math-emu/math-emu.o
+endif
+
ifdef CONFIG_XMON
SUBDIRS += arch/ppc/xmon
CORE_FILES += arch/ppc/xmon/x.o
diff -ur linux-mpc8xx-2.2.13/arch/ppc/config.in linux/arch/ppc/config.in
--- linux-mpc8xx-2.2.13/arch/ppc/config.in Fri Oct 22 14:56:10 1999
+++ linux/arch/ppc/config.in Wed Dec 1 16:29:14 1999
@@ -37,6 +37,15 @@
if [ "$CONFIG_ALL_PPC" != "y" ];then
define_bool CONFIG_MACH_SPECIFIC y
fi
+
+if [ "$CONFIG_8xx" = "y" ]; then
+ bool 'Math emulation' CONFIG_MATH_EMULATION
+else
+ if [ "$CONFIG_PPC64" != "y" ];then
+ define_bool CONFIG_6xx y
+ fi
+fi
+
endmenu
mainmenu_option next_comment
diff -ur linux-mpc8xx-2.2.13/arch/ppc/kernel/Makefile linux/arch/ppc/kernel/Makefile
--- linux-mpc8xx-2.2.13/arch/ppc/kernel/Makefile Fri Oct 22 15:21:39 1999
+++ linux/arch/ppc/kernel/Makefile Thu Dec 2 10:34:19 1999
@@ -30,7 +30,7 @@
endif
ifeq ($(CONFIG_8xx),y)
-O_OBJS += m8xx_setup.o softemu8xx.o ppc8xx_pic.o
+O_OBJS += m8xx_setup.o ppc8xx_pic.o
ifdef CONFIG_PCI
O_OBJS += qspan_pci.o
endif
diff -ur linux-mpc8xx-2.2.13/arch/ppc/kernel/traps.c linux/arch/ppc/kernel/traps.c
--- linux-mpc8xx-2.2.13/arch/ppc/kernel/traps.c Fri Oct 22 14:04:09 1999
+++ linux/arch/ppc/kernel/traps.c Thu Dec 2 10:32:22 1999
@@ -230,12 +230,12 @@
SoftwareEmulation(struct pt_regs *regs)
{
int errcode;
- extern int Soft_emulate_8xx (struct pt_regs *regs);
+ extern int do_mathemu(struct pt_regs *regs);
extern void print_8xx_pte(struct mm_struct *, unsigned long);
if (user_mode(regs))
{
- if ((errcode = Soft_emulate_8xx(regs))) {
+ if ((errcode = do_mathemu(regs))) {
printk("Software Emulation %s/%d NIP: %lx *NIP: 0x%x code: %x",
current->comm,current->pid,
regs->nip, *((uint *)regs->nip), errcode);
diff -ur linux-mpc8xx-2.2.13/include/asm-ppc/processor.h linux/include/asm-ppc/processor.h
--- linux-mpc8xx-2.2.13/include/asm-ppc/processor.h Fri Oct 22 16:10:02 1999
+++ linux/include/asm-ppc/processor.h Wed Dec 1 16:56:20 1999
@@ -57,8 +57,33 @@
#define HID0_BTCD (1<<1) /* Branch target cache disable */
/* fpscr settings */
-#define FPSCR_FX (1<<31)
-#define FPSCR_FEX (1<<30)
+#define FPSCR_FX 0x80000000 /* FPU exception summary */
+#define FPSCR_FEX 0x40000000 /* FPU enabled exception summary */
+#define FPSCR_VX 0x20000000 /* Invalid operation summary */
+#define FPSCR_OX 0x10000000 /* Overflow exception summary */
+#define FPSCR_UX 0x08000000 /* Underflow exception summary */
+#define FPSCR_ZX 0x04000000 /* Zero-devide exception summary */
+#define FPSCR_XX 0x02000000 /* Inexact exception summary */
+#define FPSCR_VXSNAN 0x01000000 /* Invalid op for SNaN */
+#define FPSCR_VXISI 0x00800000 /* Invalid op for Inv - Inv */
+#define FPSCR_VXIDI 0x00400000 /* Invalid op for Inv / Inv */
+#define FPSCR_VXZDZ 0x00200000 /* Invalid op for Zero / Zero */
+#define FPSCR_VXIMZ 0x00100000 /* Invalid op for Inv * Zero */
+#define FPSCR_VXVC 0x00080000 /* Invalid op for Compare */
+#define FPSCR_FR 0x00040000 /* Fraction rounded */
+#define FPSCR_FI 0x00020000 /* Fraction inexact */
+#define FPSCR_FPRF 0x0001f000 /* FPU Result Flags */
+#define FPSCR_FPCC 0x0000f000 /* FPU Condition Codes */
+#define FPSCR_VXSOFT 0x00000400 /* Invalid op for software request */
+#define FPSCR_VXSQRT 0x00000200 /* Invalid op for square root */
+#define FPSCR_VXCVI 0x00000100 /* Invalid op for integer convert */
+#define FPSCR_VE 0x00000080 /* Invalid op exception enable */
+#define FPSCR_OE 0x00000040 /* IEEE overflow exception enable */
+#define FPSCR_UE 0x00000020 /* IEEE underflow exception enable */
+#define FPSCR_ZE 0x00000010 /* IEEE zero divide exception enable */
+#define FPSCR_XE 0x00000008 /* FP inexact exception enable */
+#define FPSCR_NI 0x00000004 /* FPU non IEEE-Mode */
+#define FPSCR_RN 0x00000003 /* FPU rounding control */
#define _MACH_prep 1
#define _MACH_Pmac 2 /* pmac or pmac clone (non-chrp) */
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