Add function to read floating point value from address.

This is the same as "DPEEK()" for integers or "$()" for strings.

Author: dmsc

manual.md

@@ -955,6 +955,10 @@ with the hardware. Use with care!
       x = ADR("Hello")
       ? $( x )
 
+- %(_n_) :
+  This returns the floating-point
+  value stored at memory address _n_.
+
 
 List Of Statements
 ==================

src/syntax/float.syn

@@ -82,6 +82,7 @@ FP_FUNCS:
         "COs"   FP_T_EXPR emit TOK_FP_COS
         "Val"   STR_PAR_EXPR emit TOK_FP_VAL
         "RNd()" emit TOK_FP_RND
+        "%"     PAR_EXPR emit TOK_FP_LOAD
 
 ADR_EXPR:
         emit { TOK_VAR_LOAD, VT_ARRAY_FLOAT  } E_VAR_SEARCH "%"

testsuite/tests/floatadr.bas

@@ -0,0 +1,22 @@
+' Procedure to sum N elements of an array:
+PROC SUM P N
+  SUM% = 0
+  WHILE N>0
+    DEC N
+    SUM% = SUM% + %(P)
+    P = P + 6
+  WEND
+ENDPROC
+
+DIM A%(2)
+A%(0) = 0.125
+A%(1) = 0.0625
+A%(2) = 0.03125
+
+@SUM &A%, 3
+? SUM%
+
+X%=1234.5
+
+@SUM &X%, 1
+? SUM%

testsuite/tests/floatadr.chk

@@ -0,0 +1,5 @@
+Name: Test for using address of floating point vars
+Test: run-fp
+Output:
+0.21875
+1234.5