trying to re-instate SBus compatibility

nubus-to-ztex-gateware/blit_goblin.c

@@ -9,13 +9,21 @@
 #warning "Using default BASE_FB"
 #endif
 
+#if defined(GOBLIN_NUBUS)
 #define BASE_ROM 0xF0910000 // FIXME : should be generated ; 4-64 KiB of Wishbone ROM ? ; also in the LDS file ; also in the Vex config
-
 #define BASE_RAM 0xF0902000 // FIXME : should be generated : 4-64 KiB of Wishbone SRAM ? ; also in _start
 #define BASE_RAM_SIZE 0x00001000 // FIXME : should be generated : 4-64 KiB of Wishbone SRAM ? ; also in _start
-
 #define BASE_BT_REGS    0xF0900000
 #define BASE_ACCEL_REGS 0xF0901000
+#elif defined(GOBLIN_SBUS)
+#define BASE_ROM 0x00410000 // FIXME : should be generated ; 4-64 KiB of Wishbone ROM ? ; also in the LDS file ; also in the Vex config
+#define BASE_RAM 0x00420000 // FIXME : should be generated : 4-64 KiB of Wishbone SRAM ? ; also in _start
+#define BASE_RAM_SIZE 0x00001000 // FIXME : should be generated : 4-64 KiB of Wishbone SRAM ? ; also in _start
+#define BASE_BT_REGS    0x00200000
+#define BASE_ACCEL_REGS 0x000c0000
+#else
+#error "Must define GOBLIN_NUBUS or GOBLIN_SBUS"
+#endif
 
 //typedef void (*boot_t)(void);
 //typedef void (*start_t)(unsigned short, unsigned short, unsigned short, unsigned short, unsigned short, unsigned short, unsigned short, unsigned short);
@@ -173,7 +181,13 @@ asm(".global _start\n"
 	//"slli a0,a0,12\n" // 0x00001000, BASE_RAM_SIZE
 	//"add sp,sp,a0\n" // SP at the end of the SRAM
 	"nop\n"
+#if defined(GOBLIN_NUBUS)
 	"li sp, 0xF0902ffc\n" // SP at the end of the SRAM
+#elif defined(GOBLIN_SBUS)
+	"li sp, 0x00420ffc\n" // SP at the end of the SRAM
+#else
+#error "Must define GOBLIN_NUBUS or GOBLIN_SBUS"
+#endif
 	//"li a0, 0x00700968\n" // @ of r5_cmd
 	//"li a1, 0x00C0FFEE\n"
 	//"sw a1, 0(a0)\n"

nubus-to-ztex-gateware/blit_goblin.sh

@@ -18,7 +18,7 @@ OBJCOPY=${GCCDIR}/bin/${GCCPFX}objcopy
 OPT=-O3 #-fno-inline
 ARCH=rv32im_zba_zbb_zbt
 
-PARAM="-DBASE_FB=${BASE_FB}"
+PARAM="-DBASE_FB=${BASE_FB} -DGOBLIN_NUBUS"
 
 if test "x$1" != "xASM"; then
 	$GCC $OPT -S -o blit_goblin.s $PARAM -march=$ARCH -mabi=ilp32 -mstrict-align -fno-builtin-memset -nostdlib -ffreestanding -nostartfiles blit_goblin.c

nubus-to-ztex-gateware/goblin_fb.py

@@ -27,12 +27,12 @@ omap_layout = [
     ("data", 8),
 ]
 
-def goblin_rounded_size(hres, vres):
+def goblin_rounded_size(hres, vres, bus="NuBus"):
     mib = int(ceil(((hres * vres) + 0) / 1048576))
-    if (mib > 0 and mib < 8): # FIXME : NuBus
+    if (mib > 0 and mib < 8 and (bus == "NuBus")): # FIXME : NuBus
         mib = 8
-    #if (mib > 0 and mib < 16): # FIXME : SBus
-    #    mib = 16
+    if (mib > 0 and mib < 16 and (bus == "SBus")): # FIXME : SBus
+        mib = 16
     if (mib > 16 or mib < 1):
         print(f"{mib} mebibytes framebuffer not supported")
         assert(False)
@@ -438,6 +438,9 @@ class goblin(Module, AutoCSR):
         soc.add_constant("VIDEO_FRAMEBUFFER_HRES", hres)
         soc.add_constant("VIDEO_FRAMEBUFFER_VRES", vres)
 
+        # Wishbone
+        self.bus = bus = wishbone.Interface()
+
         # HW Cursor
 
         if (hwcursor):
@@ -451,8 +454,6 @@ class goblin(Module, AutoCSR):
         else:
             handle_hwcursor = [ ]
 
-        self.bus = bus = wishbone.Interface()
-
         # current cmap logic for the goblin, similar to the cg6, minus the HW cursor
         
         bt_mode = Signal(8, reset = 0x3) # bit depth is 2^x ; 0x10 is direct mode (32 bits)