add comment and sim build rule

diff --git a/Makefile b/Makefile
old mode 100644 (file)
new mode 100755 (executable)
index cd766fa..b7b04ce
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,9 @@ PART = xc3s1200e-fg320-5
 
 all: fpga_target
 
+sim: mandelsim.c
+       gcc -O3 -lSDL -o mandelsim mandelsim.c -march=pentium3
+
 BITGEN_OPTS = \
        -w \
        -g DebugBitstream:No \

diff --git a/mandelsim.c b/mandelsim.c
index 16bdf466ecc57ce972357d0f19ab3089f68adc38..2ce2feb3f3ea81cf3b36a38d1834599dd30916d4 100644 (file)
--- a/mandelsim.c
+++ b/mandelsim.c
@@ -5,6 +5,9 @@
 #define YRES 480
 #define MAX_ITER 66
 #define MAXNUM 0x8000
+
+/* be sure to change the number of bits in the multiplier when doing this
+ * bits > 14 need extension of num_t to unsigned int */
 #define BITS 14
 #define BAIL (1 << (BITS + 1))
 #define BAIL_A (1 << BITS)