> On Jun 24, 2018, at 2:30 PM, Richard Henderson <richard.hender...@linaro.org> > wrote: > > On 06/24/2018 06:46 AM, Programmingkid wrote: >>> Even in your referenced PDF, table 3-13, it says that frD is unmodified. >> >> Actually it says when FPSCR[ZE] is set is when frD is unmodified. When >> FPSCR[ZE] is not set it frD's sign is determined by an XOR of the signs of >> the operands. I have verified that this is what happens on real PowerPC 750 >> and 950 CPUs. > > > Of course. When ZE is not set, 1 / 0 -> inf (and -1 / 0 -> -inf, etc). > But ZE not set is not the topic of discussion, or the subject of your patch.
I do believe the ZE is closely tied to the fdiv instruction, and that fixing the fdiv instruction does involve the ZE bit. >> I was just wondering are you able to run a PowerPC operating system in QEMU >> in KVM mode on this Power7 computer? > > Sadly not. KVM is not enabled in this setup. Ok. Thanks for letting me know. Attached is my floating point test program. It is made for PowerPC. Does this program run on your system? If so, could you send me the results?
main.c
Description: Binary data
/**************************************************************************************
* File: main.c
* Date: 4-30-2017
* Description: Implement a test program for various floating point
instructions.
* Note: tests made to work with PowerPC G3 and G5 only.
* Compiling on Mac OS X: use gcc-3.3 -force_cpusubtype_ALL
* Note: fsqrt test will not work on PowerPC G3.
* Version: 2
**************************************************************************************/
#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <float.h>
#include <inttypes.h>
// Used to convert unsigned integer <--> double
union Converter
{
double d; // double
uint64_t i; // integer
};
typedef union Converter Converter;
/* Describes the name and description of each bit of the FPSCR */
struct fpscr_info
{
char name[8];
char description[100];
};
struct fpscr_info finfo[] =
{
"FX", "Floating-point exception summary",
"FEX", "Floating-point enabled exception summary",
"VX", "Floating-point invalid operation exception summary",
"OX", "Floating-point overflow exception",
"UX", "Floating-point underflow exception",
"ZX", "Floating-point zero divide exception",
"XX", "Floating-point inexact exception",
"VXSNAN", "Floating-point invalid operation exception for SNaN",
"VXISI", "Floating-point invalid operation exception for ∞ - ∞",
"VXIDI", "Floating-point invalid operation exception for ∞/∞",
"VXZDZ", "Floating-point invalid operation exception for 0/0",
"VXIMZ", "Floating-point invalid operation exception for ∞ * 0",
"VXVC", "Floating-point invalid operation exception for invalid compare",
"FR", "Floating-point fraction rounded",
"FI", "Floating-point fraction inexact",
"FPRF", "Floating-point result class descriptor ",
"FPRF", "Floating-point less than or negative",
"FPRF", "Floating-point greater than or positive",
"FPRF", "Floating-point equal or zero",
"FPRF", "Floating-point unordered or NaN",
"NO NAME", "Reserved - you shouldn't be seeing this",
"VXSOFT", "Floating-point invalid operation exception for software request",
"VXSQRT", "Floating-point invalid operation exception for invalid square
root",
"VXCVI", "Floating-point invalid operation exception for invalid integer
convert",
"VE", "Floating-point invalid operation exception enable",
"OE", "IEEE floating-point overflow exception enable",
"UE", "IEEE floating-point underflow exception enable",
"ZE", "IEEE floating-point zero divide exception enable",
"XE", "Floating-point inexact exception enable",
"NI", "Floating-point non-IEEE mode",
"RN", "Rounding bit 0",
"RN", "Rounding bit 1",
};
// Prints all the FPSCR settings that are set in the input
void print_fpscr_settings(uint32_t fpscr)
{
int i;
for (i = 0; i < 32; i++) {
if (((fpscr >> i) & 0x1) == 1) {
/* right description = 31 - i Oddity of IBM documentation */
printf("bit %d: %s - %s\n", 31-i, finfo[31-i].name,
finfo[31-i].description);
}
}
}
#define ZE 27
#define set_fpscr_bit(x) asm volatile ("mtfsb1 %0" : : "i"(x))
/* Keeps track of the number of tests that failed */
int failed_tests = 0;
// Reset the FPSCR
void reset_fpscr()
{
asm volatile("mtfsb0 0");
asm volatile("mtfsb0 1");
asm volatile("mtfsb0 2");
asm volatile("mtfsb0 3");
asm volatile("mtfsb0 4");
asm volatile("mtfsb0 5");
asm volatile("mtfsb0 6");
asm volatile("mtfsb0 7");
asm volatile("mtfsb0 8");
asm volatile("mtfsb0 9");
asm volatile("mtfsb0 10");
asm volatile("mtfsb0 11");
asm volatile("mtfsb0 12");
asm volatile("mtfsb0 13");
asm volatile("mtfsb0 14");
asm volatile("mtfsb0 15");
asm volatile("mtfsb0 16");
asm volatile("mtfsb0 17");
asm volatile("mtfsb0 18");
asm volatile("mtfsb0 19");
asm volatile("mtfsb0 20");
asm volatile("mtfsb0 21");
asm volatile("mtfsb0 22");
asm volatile("mtfsb0 23");
asm volatile("mtfsb0 24");
asm volatile("mtfsb0 25");
asm volatile("mtfsb0 26");
asm volatile("mtfsb0 27");
asm volatile("mtfsb0 28");
asm volatile("mtfsb0 29");
asm volatile("mtfsb0 30");
asm volatile("mtfsb0 31");
/* Check if everything is alright */
uint32_t fpscr;
Converter c;
asm volatile("mffs %0" : "=f"(c.d));
fpscr = (uint32_t)c.i;
if (fpscr != 0) {
printf("Warning: fpscr not equal to zero: 0x%x\n", fpscr);
print_fpscr_settings(fpscr);
}
}
/*
* The action to take if a test fails
* Input one: message string
* Input two: actual fpscr value
* Input three: expected fpscr value
* Input four: actual answer
* Input five: expected answer
*/
void test_failed(const char *message, uint32_t actual_fpscr, uint32_t
expected_fpscr,
uint64_t actual_answer, uint64_t expected_answer)
{
printf("%s\n", message);
printf("expected answer: 0x%" PRIx64 " (%f)\n", expected_answer,
expected_answer);
printf(" actual answer: 0x%" PRIx64 " (%f)\n", actual_answer,
actual_answer);
printf("expected fpscr: 0x%x\n", expected_fpscr);
printf(" actual fpscr: 0x%x\n", actual_fpscr);
/* Only print FPSCR bits if there is a difference */
if (actual_fpscr != expected_fpscr) {
printf("\nactual FPSCR bits set:\n");
print_fpscr_settings(actual_fpscr);
printf("\nexpected FPSCR bits set:\n");
print_fpscr_settings(expected_fpscr);
}
printf("\n");
failed_tests++;
}
/*
* Returns the value of the FPSCR
* output: unsigned 32 bit integer
*/
uint32_t get_fpscr()
{
asm volatile("mffs f0");
asm volatile("stfd f0, 40(r1)");
uint32_t return_value;
asm volatile("lwz %0, 44(r1)" : "=r"(return_value));
return return_value;
}
/* The fpscr and answer have to be right for a test to pass. */
/* Test the fadd instruction */
void test_fadd()
{
Converter c;
uint64_t expected_answer = 0x3ff3333333333334;
uint32_t actual_fpscr, expected_fpscr = 0x82064000;
reset_fpscr();
asm volatile("fadd %0, %1, %2" : "=f"(c.d) : "f"(0.4), "f"(0.8));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fadd test passed\n");
} else {
test_failed("fadd test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fadds instruction */
void test_fadds()
{
Converter c;
uint64_t expected_answer = 0x407024d500000000;
uint32_t actual_fpscr, expected_fpscr = 0x82064000;
reset_fpscr();
asm volatile("fadds %0, %1, %2" : "=f"(c.d) : "f"(257.445), "f"(0.857));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fadds test passed\n");
} else {
test_failed("fadds test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fsub instruction */
void test_fsub()
{
Converter c;
uint64_t expected_answer = 0x40f2fd1deb11c6d2;
uint32_t actual_fpscr, expected_fpscr = 0x4000;
reset_fpscr();
asm volatile("fsub %0, %1, %2" : "=f"(c.d) : "f"(123456.78),
"f"(45678.91011));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fsub test passed\n");
} else {
test_failed("fsub test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fsubs instruction */
void test_fsubs()
{
Converter c;
double expected_answer = 0x40884e3d70a3d70a;
uint32_t actual_fpscr, expected_fpscr = 0x4000;
reset_fpscr();
asm volatile("fsub %0, %1, %2" : "=f"(c.d) : "f"(1234.56), "f"(456.78));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fsubs test passed\n");
} else {
test_failed("fsubs test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test infinity - infinity */
void test_inf_minus_inf()
{
Converter c;
uint64_t expected_answer = 0x7ff8000000000000;
uint32_t actual_fpscr, expected_fpscr = 0xa0811000;
reset_fpscr();
asm volatile("fsub %0, %1, %1" : "=f"(c.d) : "f"(INFINITY));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("inf - inf test passed\n");
} else {
test_failed("inf - inf test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test division by zero */
void test_division_by_zero()
{
Converter c;
uint64_t expected_answer = 0x0;
uint32_t actual_fpscr, expected_fpscr = 0xc4000010;
reset_fpscr();
set_fpscr_bit(ZE);
asm volatile("fdiv %0, %1, %2" : "=f"(c.d) : "f"(1.0), "f"(0.0));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("division by zero test passed\n");
} else {
test_failed("division by zero test failed", actual_fpscr,
expected_fpscr, c.i, expected_answer);
}
}
/* Test zero divided by zero */
void test_zero_div_zero()
{
Converter c;
uint64_t expected_answer = 0x7ff8000000000000;
uint32_t actual_fpscr, expected_fpscr = 0xa0211010;
reset_fpscr();
set_fpscr_bit(ZE);
asm volatile("fdiv %0, %1, %1" : "=f"(c.d) : "f"(0.0), "f"(0.0));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("0/0 test passed\n");
} else {
test_failed("0/0 test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test infinity divided by infinity */
void test_inf_div_inf()
{
Converter c;
uint64_t expected_answer = 0x7ff8000000000000;
uint32_t actual_fpscr, expected_fpscr = 0xa0411000;
reset_fpscr();
asm volatile("fdiv %0, %1, %1" : "=f"(c.d) : "f"(INFINITY));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("inf/inf test passed\n");
} else {
test_failed("inf/inf test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fdiv instruction */
void test_fdiv()
{
Converter c;
uint64_t expected_answer = 0x40059f38ee13b48b;
uint32_t actual_fpscr, expected_fpscr = 0x82064000;
reset_fpscr();
asm volatile("fdiv %0, %1, %2" : "=f"(c.d) : "f"(1234.56), "f"(456.78));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fdiv test passed\n");
} else {
test_failed("fdiv test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fdivs instruction */
void test_fdivs()
{
Converter c;
uint64_t expected_answer = 0x40059f38e0000000;
uint32_t actual_fpscr, expected_fpscr = 0x82024000;
reset_fpscr();
asm volatile("fdivs %0, %1, %2" : "=f"(c.d) : "f"(1234.56), "f"(456.78));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fdivs test passed\n");
} else {
test_failed("fdivs test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fmul instruction */
void test_fmul()
{
Converter c;
uint64_t expected_answer = 0x40365c28f5c28f5c;
uint32_t actual_fpscr, expected_fpscr = 0x82024000;
reset_fpscr();
asm volatile("fmul %0, %1, %2" : "=f"(c.d) : "f"(5.2), "f"(4.3));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fmul test passed\n");
} else {
test_failed("fmul test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fmuls instruction */
void test_fmuls()
{
Converter c;
uint64_t expected_answer = 0x412135a4a0000000;
uint32_t actual_fpscr, expected_fpscr = 0x82024000;
reset_fpscr();
asm volatile("fmuls %0, %1, %2" : "=f"(c.d) : "f"(1234.56), "f"(456.78));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fmuls test passed\n");
} else {
test_failed("fmuls test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fmul instruction */
void test_inf_times_zero()
{
Converter c;
uint64_t expected_answer = 0x7ff8000000000000;
uint32_t actual_fpscr, expected_fpscr = 0xa0111000;
reset_fpscr();
asm volatile("fmul %0, %1, %2" : "=f"(c.d) : "f"(INFINITY), "f"(0.0));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("inf * 0 test passed\n");
} else {
test_failed("inf * 0 test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fmadd instruction */
void test_fmadd()
{
Converter c;
uint64_t expected_answer = 0x4123fcaadfa43fe5;
uint32_t actual_fpscr, expected_fpscr = 0x82024000;
reset_fpscr();
asm volatile("fmadd %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),
"f"(456.78), "f"(91011.12));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fmadd test passed\n");
} else {
test_failed("fmadd test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fmadds instruction */
void test_fmadds()
{
Converter c;
uint64_t expected_answer = 0x4123fcaae0000000;
uint32_t actual_fpscr, expected_fpscr = 0x82064000;
reset_fpscr();
asm volatile("fmadds %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),
"f"(456.78), "f"(91011.12));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fmadds test passed\n");
} else {
test_failed("fmadds test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fsqrt instruction - This instruction doesn't work on the PowerPC
750 (G3).
It does work on the PowerPC 970 (G5). */
/*void test_fsqrt()
{
double answer;
reset_fpscr();
asm volatile("fsqrt %0, %1" : "=f"(answer) : "f"(-1.0));
if (get_fpscr() == 0xa0011200) {
printf("fsqrt test passed\n");
} else {
test_failed("fsqrt test failed");
}
}*/
/* Test an overflow condition */
void test_overflow()
{
// multiplying two really big numbers equals overflow
Converter c;
double really_big_input;
uint64_t expected_answer = 0x7ff0000000000000;
uint32_t actual_fpscr, expected_fpscr = 0x92025000;
reset_fpscr();
really_big_input = 1.7 * pow(10, 308);
asm volatile("fmul %0, %1, %1" : "=f"(c.d) : "f"(really_big_input));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("overflow test passed\n");
} else {
test_failed("overflow test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test an underflow condition */
void test_underflow()
{
Converter c;
uint64_t expected_answer = 0x199999999999a;
uint32_t actual_fpscr, expected_fpscr = 0x8a074000;
reset_fpscr();
asm volatile("fmadd %0, %1, %2, %3" : "=f"(c.d) : "f"(DBL_MIN), "f"(0.1),
"f"(0.0));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("underflow test passed\n");
} else {
test_failed("underflow test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fctiw instruction */
void test_fctiw()
{
Converter c;
uint64_t expected_answer;
uint32_t actual_fpscr, expected_fpscr;
double frB;
/* above maximum value test */
expected_fpscr = 0xa0000100;
expected_answer = 0x7fffffff;
frB = pow(2, 32); // greater than 2^31 - 1
reset_fpscr();
asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(frB));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiw above maximum value test passed\n");
} else {
test_failed("fctiw above maximum value test failed", actual_fpscr,
expected_fpscr, (c.i & 0xffffffff), expected_answer);
}
/* below minimum value test*/
expected_fpscr = 0xa0000100;
expected_answer = 0x80000000;
frB = -frB; // less than -2^31
reset_fpscr();
asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(frB));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiw below minimum value test passed\n");
} else {
test_failed("fctiw below minimum value test failed", actual_fpscr,
expected_fpscr, (c.i & 0xffffffff), expected_answer);
}
/* float to integer test */
expected_fpscr = 0x82060000;
expected_answer = 0xd;
reset_fpscr();
asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(12.7));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiw integer conversion test passed\n");
} else {
test_failed("fctiw integer conversion test failed", actual_fpscr,
expected_fpscr, c.i, expected_answer);
}
}
/* Test the fctiwz instruction */
void test_fctiwz()
{
Converter c;
uint64_t expected_answer;
uint32_t actual_fpscr, expected_fpscr;
double frB;
/* above maximum value test */
expected_fpscr = 0xa0000100;
expected_answer = 0x7fffffff;
frB = pow(2, 32); // greater than 2^31 - 1
reset_fpscr();
asm volatile("fctiwz %0, %1" : "=f"(c.d) : "f"(frB));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiwz above maximum value test passed\n");
} else {
test_failed("fctiwz above maximum value test failed", actual_fpscr,
expected_fpscr, (c.i & 0xffffffff), expected_answer);
}
/* below minimum value test*/
expected_fpscr = 0xa0000100;
expected_answer = 0x80000000;
frB = -frB; // less than -2^31
reset_fpscr();
asm volatile("fctiwz %0, %1" : "=f"(c.d) : "f"(frB));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiwz below minimum value test passed\n");
} else {
test_failed("fctiwz below minimum value test failed", actual_fpscr,
expected_fpscr, (c.i & 0xffffffff), expected_answer);
}
/* float to integer test */
expected_fpscr = 0x82060000;
expected_answer = 0x1c;
reset_fpscr();
asm volatile("fctiw %0, %1" : "=f"(c.d) : "f"(27.98));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && (c.i & 0xffffffff) ==
expected_answer) {
printf("fctiwz integer conversion test passed\n");
} else {
test_failed("fctiwz integer conversion test failed", actual_fpscr,
expected_fpscr, c.i, expected_answer);
}
}
/* Test the frsp instruction */
void test_frsp()
{
Converter c;
uint64_t expected_answer = 0x4271f71fc0000000;
uint32_t actual_fpscr, expected_fpscr = 0x82064000;
reset_fpscr();
asm volatile("frsp %0, %1" : "=f"(c.d) : "f"(1234567891012.131415));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("frsp test passed\n");
} else {
test_failed("frsp test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Test the fnmsub instruction */
void test_fnmsub()
{
Converter c;
uint64_t expected_answer = 0xc11cdd3cc985f06e;
uint32_t actual_fpscr, expected_fpscr = 0x82028000;
reset_fpscr();
asm volatile("fnmsub %0, %1, %2, %3" : "=f"(c.d) : "f"(1234.56),
"f"(456.78), "f"(91011.12));
actual_fpscr = get_fpscr();
if (actual_fpscr == expected_fpscr && c.i == expected_answer) {
printf("fnmsub test passed\n");
} else {
test_failed("fnmsub test failed", actual_fpscr, expected_fpscr, c.i,
expected_answer);
}
}
/* Report the results of all the tests */
void report_results()
{
if (failed_tests == 1) {
printf("\n=== Warning: %d test failed ===\n", failed_tests);
} else if (failed_tests > 1) {
printf("\n=== Warning: %d tests failed ===\n", failed_tests);
} else {
printf("\n=== All tests passed ===\n");
}
}
int main (int argc, const char * argv[]) {
test_fadd();
test_fadds();
test_fsub();
test_fsubs();
test_fmul();
test_fmuls();
test_fdiv();
test_fdivs();
test_fmadd();
test_fmadds();
//test_fsqrt();
test_inf_minus_inf();
test_division_by_zero();
test_zero_div_zero();
test_inf_div_inf();
test_inf_times_zero();
test_overflow();
test_underflow();
test_fctiw();
test_fctiwz();
test_frsp();
test_fnmsub();
report_results();
return 0;
}
