forked from Github_Repos/cvw
54 lines
1.5 KiB
C
54 lines
1.5 KiB
C
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// softfloat_demo.c
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// David_Harris@hmc.edu 27 February 2022
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//
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// Demonstrate using SoftFloat do compute a floating-point, then print results
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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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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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conv.v = f.v; // use union to convert between hexadecimal and floating-point views
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printf ("%s: 0x%08x = %g\n", msg, conv.v, 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 ("exceptions: 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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// rounding modes: RNE: softfloat_round_near_even
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// RZ: softfloat_round_minMag
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// RP: softfloat_round_max
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// RM: softfloat_round_min
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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_beforeRounding; // RISC-V behavior for tininess
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}
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int main()
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{
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float32_t x, y, z, r;
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x.v = 0x3fc00000;
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y.v = 0x3fc00000;
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z.v = 0x00000001;
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softfloatInit();
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r = f32_mulAdd(x, y, z);
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printF32("X", x); printF32("Y", y); printF32("Z", z);
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printF32("result = X*Y+Z", r); printFlags();
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}
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