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78 lines
2.0 KiB
C
78 lines
2.0 KiB
C
//
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// softfloat_div.c
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// james.stine@okstate.edu 12 April 2023
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//
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// Demonstrate using SoftFloat to compute 754 fp divide, then print results
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// (adapted from original C built by David Harris)
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//
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#include <stdio.h>
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#include <stdint.h>
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#include "softfloat.h"
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#include "softfloat_types.h"
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typedef union sp {
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uint32_t v;
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unsigned short x[2];
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float f;
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} sp;
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void printF32 (char *msg, float32_t f) {
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sp conv;
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int i, j;
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conv.v = f.v; // use union to convert between hexadecimal and floating-point views
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printf("%s: ", msg); // print out nicely
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printf("0x%04x_%04x = %1.15g\n", (conv.v >> 16),(conv.v & 0xFFFF), conv.f);
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}
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void printFlags(void) {
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int NX = softfloat_exceptionFlags % 2;
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int UF = (softfloat_exceptionFlags >> 1) % 2;
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int OF = (softfloat_exceptionFlags >> 2) % 2;
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int DZ = (softfloat_exceptionFlags >> 3) % 2;
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int NV = (softfloat_exceptionFlags >> 4) % 2;
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printf ("Flags: Inexact %d Underflow %d Overflow %d DivideZero %d Invalid %d\n",
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NX, UF, OF, DZ, NV);
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}
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void softfloatInit(void) {
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// RNE: softfloat_round_near_even
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// RZ: softfloat_round_minMag
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// RU: softfloat_round_max
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// RD: softfloat_round_min
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// RM: softfloat_round_near_maxMag
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softfloat_roundingMode = softfloat_round_near_even;
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softfloat_exceptionFlags = 0; // clear exceptions
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softfloat_detectTininess = softfloat_tininess_afterRounding; // RISC-V behavior for tininess
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}
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int main() {
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// float32_t is typedef in SoftFloat
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float32_t x, y, r1, r2;
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sp convx, convy;
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// Choose two random values
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convx.f = 1.30308703073;
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convy.f = 1.903038030370;
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// Convert to SoftFloat format
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x.v = (convx.x[1] << 16) + convx.x[0];
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y.v = (convy.x[1] << 16) + convy.x[0];
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printf("Example using SoftFloat\n");
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softfloatInit();
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r1 = f32_div(x, y);
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printf("-------\n");
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printF32("X", x);
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printF32("Y", y);
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printF32("result = X/Y", r1);
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printFlags();
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r2 = f32_sqrt(x);
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printf("-------\n");
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printF32("X", x);
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printF32("result = sqrt(X)", r2);
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printFlags();
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}
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