Add ln2 floating point constant

mehfooz09 · Oct 30, 2018 · de81156 · de81156
1 parent c10fac1
commit de81156
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Showing 4 changed files with 12 additions and 10 deletions.
diff --git a/emu/decode.h b/emu/decode.h
@@ -606,6 +606,7 @@ __no_instrument DECODER_RET glue(DECODER_NAME, OP_SIZE)(DECODER_ARGS) {
                     case 0xd940: TRACE("fchs"); FCHS(); break;
                     case 0xd941: TRACE("fabs"); FABS(); break;
                     case 0xd950: TRACE("fld1"); FLDC(one); break;
+                    case 0xd955: TRACE("fldln2"); FLDC(ln2); break;
                     case 0xd956: TRACE("fldz"); FLDC(zero); break;
                     case 0xd970: TRACE("fprem"); FPREM(); break;
                     case 0xd974: TRACE("frndint"); FRNDINT(); break;

diff --git a/emu/fpu.c b/emu/fpu.c
@@ -27,12 +27,7 @@ void fpu_ld(struct cpu_state *cpu, int i) {
 }
 
 void fpu_ldc(struct cpu_state *cpu, enum fpu_const c) {
-    switch (c) {
-        case fconst_zero:
-            fpush(f80_from_int(0)); break;
-        case fconst_one:
-            fpush(f80_from_int(1)); break;
-    }
+    fpush(fpu_consts[c]);
 }
 
 void fpu_ild32(struct cpu_state *cpu, int32_t *i) {

diff --git a/emu/fpu.h b/emu/fpu.h
@@ -1,12 +1,20 @@
 #ifndef EMU_FPU_H
 #define EMU_FPU_H
 #include "emu/float80.h"
+struct cpu_state;
 
 typedef float float32;
 typedef double float64;
 
 enum fpu_const {
-    fconst_one, fconst_zero,
+    fconst_one = 0,
+    fconst_ln2 = 5,
+    fconst_zero = 6,
+};
+static float80 fpu_consts[] = {
+    [fconst_one]  = (float80) {.signif = 0x8000000000000000, .signExp = 0x3fff},
+    [fconst_ln2]  = (float80) {.signif = 0xb17217f7d1cf79ac, .signExp = 0x3ffe},
+    [fconst_zero] = (float80) {.signif = 0x0000000000000000, .signExp = 0x0000},
 };
 
 void fpu_pop(struct cpu_state *cpu);

diff --git a/emu/interp/fpu.h b/emu/interp/fpu.h
@@ -96,9 +96,7 @@
 #define FLDM(val,z) \
     FPUSH(f80_from_float(get(val,z),z))
 
-#define FLDC(what) FPUSH(fconst_##what)
-#define fconst_one f80_from_int(1)
-#define fconst_zero f80_from_int(0)
+#define FLDC(what) FPUSH(fconsts[fconst_##what])
 
 #define FSTM(dst,z) \
     set(dst, f80_to_float(ST(0),z),z)