From: Shamus Hammons <jlhamm@acm.org>
Date: Thu, 8 Aug 2019 02:15:19 +0000 (-0500)
Subject: One more minor fix: add back FP values for 56001 in d_dc.
X-Git-Tag: v2.1.0~64
X-Git-Url: http://shamusworld.gotdns.org/cgi-bin/gitweb.cgi?p=rmac;a=commitdiff_plain;h=1df40a4f5be00b253fbb7901f8e108d994c8cb40

One more minor fix: add back FP values for 56001 in d_dc.
---

diff --git a/direct.c b/direct.c
index 32e5dd1..1864b86 100644
--- a/direct.c
+++ b/direct.c
@@ -1191,28 +1191,7 @@ int d_dc(WORD siz)
 					if (eattr & FLOAT)
 					{
 						double fval = *(double *)&eval;
-
-						if (fval >= 1)
-						{
-							warn("value clamped to +1.");
-							eval = 0x7fffff;
-						}
-						else if (fval <= -1)
-						{
-							warn("value clamped to -1.");
-							eval = 0x800000;
-						}
-						else
-						{
-							// Convert fraction to 24 bits fixed point with sign and rounding
-							// Yeah, that cast to int32_t has to be there because casting
-							// a float to unsigned int is "undefined" according to the C
-							// standard. Which most compilers seem to do the sensible thing
-							// and just cast the f**king value properly, except gcc 4.x.x
-							// for arm (tested on raspbian).
-							// Thanks, C and gcc! Thanks for making me waste a few hours \o/
-							eval = 0;//!!! FIX !!! (uint32_t)(int32_t)round(fval*(1 << 23));
-						}
+						eval = DoubleToDSPFloat(fval);
 					}
 					else
 					{
@@ -1227,10 +1206,11 @@ int d_dc(WORD siz)
 			else
 			{
 				// In L: we deposit stuff to both X: and Y: instead
-				// We will be a bit lazy and require that there is a 2nd value in the same source line.
-				// (Motorola's assembler can parse 12-digit hex values, which we can't do at the moment)
-				// This of course requires to parse 2 values in one pass.
-				// If there isn't another value in this line, assume X: value is 0.
+				// We will be a bit lazy and require that there is a 2nd value
+				// in the same source line. (Motorola's assembler can parse
+				// 12-digit hex values, which we can't do at the moment) This
+				// of course requires to parse 2 values in one pass. If there
+				// isn't another value in this line, assume X: value is 0.
 				int secondword = 0;
 				uint32_t evaly;
 l_parse_loop:
@@ -1245,27 +1225,7 @@ l_parse_loop:
 					if (eattr & FLOAT)
 					{
 						float fval = *(float *)&eval;
-						if (fval >= 1)
-						{
-							warn("value clamped to +1.");
-							eval = 0x7fffff;
-						}
-						else if (fval <= -1)
-						{
-							warn("value clamped to -1.");
-							eval = 0x800000;
-						}
-						else
-						{
-							// Convert fraction to 24 bits fixed point with sign and rounding
-							// Yeah, that cast to int32_t has to be there because casting
-							// a float to unsigned int is "undefined" according to the C
-							// standard. Which most compilers seem to do the sensible thing
-							// and just cast the f**king value properly, except gcc 4.x.x
-							// for arm (tested on raspbian).
-							// Thanks, C and gcc! Thanks for making me waste a few hours \o/
-							eval = 0;//!!! FIX !!! (uint32_t)(int32_t)round(fval*(1 << 23));
-						}
+						eval = DoubleToDSPFloat(fval);
 					}
 					else
 					{
@@ -1305,6 +1265,7 @@ l_parse_loop:
 				}
 
 			}
+
 			goto comma;
 		}
 
diff --git a/fltpoint.c b/fltpoint.c
index 8739e88..2205a79 100644
--- a/fltpoint.c
+++ b/fltpoint.c
@@ -15,6 +15,7 @@
 #include <float.h>
 #include <math.h>
 #include <stdio.h>
+#include "error.h"
 
 //
 // Check for IEEE-754 conformance (C99 compilers should be OK here)
@@ -171,6 +172,27 @@ void DoubleToExtended(double d, uint8_t out[])
 }
 
 
+//
+// Convert a double to a DSP56001 style fixed point float.
+// Seems to be 23 bits of float value with 1 bit (MSB) for the sign.
+//
+uint32_t DoubleToDSPFloat(double d)
+{
+	if (d >= 1)
+	{
+		warn("DSP value clamped to +1.");
+		return 0x7FFFFF;
+	}
+	else if (d <= -1)
+	{
+		warn("DSP value clamped to -1.");
+		return 0x800000;
+	}
+
+	return trunc(round(ldexp(d, 23)));
+}
+
+
 //
 // Convert a host native floating point number to a fixed point number.
 //
diff --git a/fltpoint.h b/fltpoint.h
index 6444ed3..9704f5e 100644
--- a/fltpoint.h
+++ b/fltpoint.h
@@ -13,6 +13,7 @@
 uint32_t FloatToIEEE754(float f);
 uint64_t DoubleToIEEE754(double d);
 void DoubleToExtended(double d, uint8_t out[]);
+uint32_t DoubleToDSPFloat(double d);
 
 uint64_t DoubleToFixedPoint(double d, int intBits, int fracBits);