From f73bb4e372604261a24c158d536105968844b78e Mon Sep 17 00:00:00 2001
From: aap <aap@papnet.eu>
Date: Mon, 25 Apr 2016 21:02:18 +0200
Subject: [PATCH] implemented FSC

---
 apr.c  | 38 +++++++++++++++++++++++++++++++++++++-
 main.c | 29 +++++++++++++++++++++++++++++
 mem    | 19 +++++++------------
 pdp6.h |  5 +++++
 4 files changed, 78 insertions(+), 13 deletions(-)

diff --git a/apr.c b/apr.c
index 1460c07..15697c6 100644
--- a/apr.c
+++ b/apr.c
@@ -39,6 +39,7 @@ swap(word *a, word *b)
 #define AR_OV_SET (apr->ar_cry0 != apr->ar_cry1)
 #define AR0_XOR_AROV (!!(apr->ar & F0) != apr->ar_cry0_xor_cry1)
 #define AR0_XOR_AR1 (!!(apr->ar & F0) != !!(apr->ar & F1))
+#define AR0_EQ_SC0 (!!(apr->ar & F0) == !!(apr->sc & 0400))
 #define SET_OVERFLOW apr->ar_ov_flag = 1, recalc_cpa_req(apr)
 
 // 6-13
@@ -473,6 +474,7 @@ pulse(lct0a);
 pulse(dct0a);
 pulse(mst2);
 pulse(mpt0a);
+pulse(fst0a);
 
 // TODO: find A LONG, it probably doesn't exist
 
@@ -532,6 +534,7 @@ pulse(ds_clr){
 	apr->dsf6 = 0;
 	apr->dsf8 = 0;
 	apr->dsf9 = 0;
+	apr->fsf1 = 0;	// 6-19
 }
 
 pulse(mr_clr){
@@ -884,6 +887,7 @@ pulse(blt_t0){
 #define SC_INC apr->sc = apr->sc+1 & 0777
 #define SC_DATA (apr->chf1 ? ~apr->mb>>30 & 077 | 0700 : \
                  apr->chf2 ? apr->mb>>24 & 077 : \
+                 apr->fsf1 || 0 ? apr->ar>>27 & 0777 : \
                  0)	// TODO
 #define SC_PAD apr->sc ^= SC_DATA
 #define SC_CRY apr->sc += (~apr->sc & SC_DATA) << 1
@@ -1000,6 +1004,7 @@ pulse(sct0){
 pulse(sat3){
 	trace("SAT3\n");
 	if(apr->chf2) nextpulse(apr, cht3a);	// 6-19
+	if(apr->fsf1) nextpulse(apr, fst0a);	// 6-19
 }
 
 pulse(sat2_1){
@@ -1534,6 +1539,30 @@ pulse(nrt6){
 	nextpulse(apr, et10);		// 5-5
 }
 
+/*
+ * Floating scale
+ */
+
+pulse(fst1){
+	trace("FST1\n");
+	SC_INC;		// 6-16
+}
+
+pulse(fst0a){
+	trace("FST0A\n");
+	apr->fsf1 = 0;	// 6-19
+	if(!AR0_EQ_SC0)
+		SET_OVERFLOW;	// 6-17
+	apr->ar |= apr->ar&0400777777777 | (apr->sc&0377)<<27;	 // 6-4
+	nextpulse(apr, et10);	// 5-5
+}
+
+pulse(fst0){
+	trace("FST0\n");
+	apr->fsf1 = 1;		// 6-19
+	nextpulse(apr, sat0);	// 6-16
+}
+
 /*
  * Fixed point multiply
  */
@@ -1991,13 +2020,20 @@ pulse(et3){
 	if(AR_P1)
 		nextpulse(apr, ar_pm1_t1);
 
+	if(IR_FPCH && !(apr->ir & H3) &&
+	   (apr->inst == 0130 || apr->inst == 0131 || !(apr->ir & H4) || !(apr->ir & H5)))
+		nextpulse(apr, st7);		// 5-6
 	if(apr->inst == BLT)
 		nextpulse(apr, blt_t0);		// 6-18
 	if(apr->shift_op)
 		nextpulse(apr, sht1);		// 6-20
+	if(apr->inst == FSC){
+		if(apr->ar & F0)
+			nextpulse(apr, fst1);	// 6-19
+		nextpulse(apr, fst0);		// 6-19
+	}
 	if(apr->inst == XCT)
 		nextpulse(apr, xct_t0);		// 5-10
-	// FSC
 	if(AR_SBR)
 		apr->et4_ar_pse = 1;		// 5-5
 	if(!ET4_INH)
diff --git a/main.c b/main.c
index 0250a76..d21e45d 100644
--- a/main.c
+++ b/main.c
@@ -3,6 +3,35 @@
 #include <SDL/SDL_image.h>
 #include <pthread.h>
 
+word dtopdp(double d){
+	uint64_t x, s, e, m;
+	word f;
+	x = *(uint64_t*)&d;
+	s = (x >> 63) & 1;
+	e = (x >> 52) & 0x7FF;
+	m = x & 0xFFFFFFFFFFFFF;
+	e -= 1023;
+	e += 128;
+	m >>= 25;
+	f = s << 35;
+	f |= e << 27;
+	f |= m;
+	return f;
+}
+double pdptod(word f){
+	uint64_t x, s, e, m;
+	s = (f >> 35) & 1;
+	e = (f >> 27) & 0377;
+	m = f & 0777777777;
+	e -= 128;
+	e += 1023;
+	m <<= 25;
+	x = s << 63;
+	x |= e << 52;
+	x |= m;
+	return *(double*)&x;
+}
+
 SDL_Surface *screen;
 
 SDL_Surface *keysurf[3];
diff --git a/mem b/mem
index e206948..ad9f964 100644
--- a/mem
+++ b/mem
@@ -1,12 +1,7 @@
-1000: 200000001006
-1001: 200040001007
-1002: 234000001010
-1003: 254200000000
-1004: 777777777742
-1005: 777777777766
-1006: 777777777777
-1007: 777777777771
-1010: 777777777775
-1011: 777777777777
-1012: 777777777772
-1013: 777777777775
+1000: 200000001003
+1001: 132000000001
+1002: 254200000000
+1003: 200000000000
+1004: 600000000000
+1005: 200400000000
+1006: 577400000000
diff --git a/pdp6.h b/pdp6.h
index e5911d8..9066c91 100644
--- a/pdp6.h
+++ b/pdp6.h
@@ -15,6 +15,10 @@ typedef uint16_t u16;
 typedef uint8_t  u8;
 typedef char bool;
 
+/* convert between PDP-6 float and ieee double */
+word dtopdp(double d);
+double pdptod(word f);
+
 enum Mask {
 	FW   = 0777777777777,
 	RT   = 0000000777777,
@@ -162,6 +166,7 @@ struct Apr {
 	bool mpf1, mpf2;
 	bool msf1;
 	bool dsf1, dsf2, dsf3, dsf4, dsf5, dsf6, dsf7, dsf8, dsf9;
+	bool fsf1;
 	bool iot_f0a;
 	bool blt_f0a, blt_f3a, blt_f5a;
 	bool uuo_f1;