[cadcdev-svn-commits] [SCM] branch master updated. v2.0.0-1396-g5ff6cd01

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- Log -----------------------------------------------------------------
commit 5ff6cd01cd9d1d47472e45c0f29d955bfe864eec
Author: Falco Girgis <gyr...@gm...>
Date:   Thu May 16 11:46:36 2024 -0500

    Updated the FPU exception example. (#572)
    
    - There's no need for inline assembly anymore, thanks to the compiler
      intrinsic for fpscr implemented by Oleg endo.
    - Show off how to reproduce even more different exception types.
    - Tested for both -m4-single-only and -m4-single

-----------------------------------------------------------------------

Summary of changes:
 examples/dreamcast/basic/fpu/exc/fpu_exc.c | 138 +++++++++++++++++++++++++----
 1 file changed, 119 insertions(+), 19 deletions(-)

diff --git a/examples/dreamcast/basic/fpu/exc/fpu_exc.c b/examples/dreamcast/basic/fpu/exc/fpu_exc.c
index 5cc5256f..718d5e0d 100644
--- a/examples/dreamcast/basic/fpu/exc/fpu_exc.c
+++ b/examples/dreamcast/basic/fpu/exc/fpu_exc.c
@@ -1,39 +1,139 @@
 /* KallistiOS ##version##
 
    fpu_exc.c
-   (c)2002 Megan Potter
+   Copyright (C) 2002 Megan Potter
+   Copyright (C) 2024 Falco Girgis
+*/
+
+/*
+    This file serves as both an example of and an automatable test case for
+    working with the SH4's FPU state and exceptions.
 */
 
 #include <kos.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <float.h>
 
-asm(
-    "	.text\n"
-    "	.align 2\n"
-    "__get_fpscr:\n"
-    "	rts\n"
-    "	sts	fpscr,r0\n"
-);
+#ifdef __SH4_SINGLE_ONLY__
+#   define SH4_FPU_CONFIG_NAME  "-m4-single-only"
+#elif defined(__SH4_SINGLE__)
+#   define SH4_FPU_CONFIG_NAME  "-m4-single"
+#else
+#   define SH4_FPU_CONFIG_NAME  "unknown"
+#endif
 
-extern uint32 _get_fpscr();
+static const char*
+fpscr_stringify(unsigned int value, char* buffer, size_t bytes) {
 
-int main(int argc, char **argv) {
-    uint32 fpscr;
-    double d = 1.0;
+    snprintf(buffer, bytes,
+            "\tFPSCR [%x]:\n"
+            "\t\tFR     = %d\n"
+            "\t\tSZ     = %d\n"
+            "\t\tPR     = %d\n"
+            "\t\tDN     = %d\n"
+            "\t\tCause  = %x\n"
+            "\t\tEnable = %x\n"
+            "\t\tFlag   = %x\n"
+            "\t\tRM     = %x\n",
+            value,
+            !!(value & (1 << 21)),
+            !!(value & (1 << 20)),
+            !!(value & (1 << 19)),
+            !!(value & (1 << 18)),
+            (value >> 12) & 0x3f,
+            (value >> 7) & 0x3f,
+            (value >> 2) & 0x3f,
+            value & 0x3);
 
-    /* Exit parachute */
-    cont_btn_callback(0, CONT_START, (cont_btn_callback_t)arch_exit);
+    return buffer;
+}
+
+static bool fpscr_test(const char *name, unsigned mask, void (*test)(void)) {
+    char buffer[512];
+    bool success = true;
+
+    const unsigned begin_fpscr = __builtin_sh_get_fpscr();
+
+    printf("Beginning %s test!\n", name);
 
-    fpscr = _get_fpscr();
-    printf("fpscr is %08x\n", (unsigned int)fpscr);
+    test();
 
+    unsigned fpscr = __builtin_sh_get_fpscr();
+    printf("%s", fpscr_stringify(fpscr, buffer, sizeof(buffer)));
+
+    if(!(fpscr & mask)) {
+        fprintf(stderr, "\tFAILURE: %s flag not asserted!\n", name);
+        success = false;
+    }
+    else {
+        printf("\tSUCCESS!\n");
+    }
+
+    __builtin_sh_set_fpscr(begin_fpscr);
+
+    return success;
+}
+
+static void fpscr_underflow(void) {
+    volatile double d = 1.0;
     while(d > 0.0) {
-        printf("%f\n", d);
+//        printf("\t%.15lf\n", d);
         d *= 0.01;
     }
+}
+
+static void fpscr_overflow(void) {
+    volatile double d = 1.0;
+    while(d < DBL_MAX) {
+//        printf("\t%.15lf\n", d);
+        d *= 1.1;
+    }
+}
+
+static void fpscr_nan(void) {
+    volatile double d = 0.0;
+    volatile double c = 0.0;
+    volatile double e = d / c;
+    (void)e;
+}
+
+static void fpscr_div_zero(void) {
+    volatile double d = 1.0;
+    volatile double c = 0.0;
+    volatile double e = d / c;
+    (void)e;
+}
+
+int main(int argc, char **argv) {
+    char buffer[512];
+    bool success = true;
 
-    printf("Underflow occurred, no exceptions!\n");
+    /* Exit parachute */
+    cont_btn_callback(0, CONT_START, (cont_btn_callback_t)arch_exit);
+
+    printf("Beginning the FPU exception test!\n");
+    printf("\tFPU Config: %s\n", SH4_FPU_CONFIG_NAME);
+    printf("\tsizeof(float): %zu\n", sizeof(float));
+    printf("\tsizeof(double): %zu\n", sizeof(double));
+
+    unsigned fpscr_start = __builtin_sh_get_fpscr();
+    printf("Original Value:\n%s", fpscr_stringify(fpscr_start, buffer, sizeof(buffer)));
+
+    success &= fpscr_test("underflow",     (1 << 3), fpscr_underflow);
+    success &= fpscr_test("overflow",      (1 << 4), fpscr_overflow);
+    success &= fpscr_test("divde-by-zero", (1 << 5), fpscr_div_zero);
+    success &= fpscr_test("NAN",           (1 << 6), fpscr_nan);
+
+    if(success) {
+        printf("\nTEST SUCCEEDED!\n");
+        return EXIT_SUCCESS;
+    }
+    else {
+        fprintf(stderr, "\nTEST FAILED!\n");
+        return EXIT_FAILURE;
+    }
 
-    return 0;
 }
 
 


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A pseudo Operating System for the Dreamcast.