Add HERESTART xcomp config

blk/280

@@ -1,16 +1,16 @@
 Z80 boot code
 
 This assembles the boot binary. It requires the Z80 assembler
-(B200) and cross compilation setup (B260). It also requires
-these constants to be set:
+(B200) and cross compilation setup (B260). It requires some
+constants to be set. See B420 for details.
 
-SYSVARS: This is where system variables are placed. HERE is
-then placed at SYSVARS+0x80 (ref B80).
+RESERVED REGISTERS: At all times, IX points to RSP TOS and IY
+is IP. SP points to PSP TOS, but you can still use the stack\
+in native code. you just have to make sure you've restored it
+before "next".
 
-RS_ADDR: to be set to the bottom address of the Return Stack.
-
-PS_ADDR: top address of the Parameter stack (PS grows down-
-wards). Allow space for stack underflow protection (B76).
-
-
-                                                        (cont.)
+STABLE ABI: The boot binary starts with a list of references.
+The address of these references have to stay to those addr-
+esses. The rest of the Collapse OS code depend on it. In fact,
+up until 0x67, the (?br) wordref, pretty much everything has
+to stay put.                                            (cont.)

blk/281

@@ -1,14 +1,3 @@
-RESERVED REGISTERS: At all times, IX points to RSP TOS and IY
-is IP. SP points to PSP TOS, but you can still use the stack\
-in native code. you just have to make sure you've restored it
-before "next".
-
-STABLE ABI: The boot binary starts with a list of references.
-The address of these references have to stay to those addr-
-esses. The rest of the Collapse OS code depend on it. In fact,
-up until 0x67, the (?br) wordref, pretty much everything has
-to stay put.
-
 The boot binary is loaded in 2 parts. The first part, "decla-
 rations", are loaded after xcomp, before xcomp overrides, with
 "282 LOAD". The rest, after xcomp overrides, with "283 335

blk/299

@@ -1,13 +1,14 @@
 PC ORG @ 1 + ! ( main )
 ( STACK OVERFLOW PROTECTION: See B76 )
     SP PS_ADDR LDdn, IX RS_ADDR LDdn,
-( HERE begins at RAMEND )
-    HL SYSVARS 0x80 + LDdn,
-    SYSVARS 0x04 + LD(n)HL, ( RAM+04 == HERE )
 ( LATEST is a label to the latest entry of the dict. It is
   written at offset 0x08 by the process or person building
   Forth. )
     BIN( @ 0x08 + LDHL(n),
     SYSVARS 0x02 ( CURRENT ) + LD(n)HL,
+HERESTART [IF]
+    HL HERESTART LDdn,
+[THEN]
+    SYSVARS 0x04 + LD(n)HL, ( RAM+04 == HERE )
     DE BIN( @ 0x04 ( BOOT ) + LDdd(n),
     JR, L1 FWR ( execute, B301 )

blk/425

@@ -1,7 +1,10 @@
 anatomy. First, we have constants. Some of them are device-
 specific, but some of them are always there. SYSVARS is the
 address at which the RAM starts on the system. System variables
-will go there and HERE will go after it.
+will go there and use 0x80 bytes. See B80.
+
+HERESTART determines where... HERE is at startup. 0 means
+"same as CURRENT".
 
 RS_ADDR is where RSP starts and PS_ADDR is where PSP starts.
 RSP and PSP are designed to be contiguous. RSP goes up and PSP
@@ -10,7 +13,4 @@ goes down. If they meet, we know we have a stack overflow.
 Then, we load the assembler and cross compilation unit, which
 will be needed for the task ahead.
 
-Then, it's a matter of adding layer after layer. For most
-system, all those layers except the drivers will be added the
-same way. Drivers are a bit tricker and machine specific. I
-can't help you there, you'll have to use your wits.     (cont.)
+                                                        (cont.)

blk/426

@@ -1,3 +1,8 @@
+Then, it's a matter of adding layer after layer. For most
+system, all those layers except the drivers will be added the
+same way. Drivers are a bit tricker and machine specific. I
+can't help you there, you'll have to use your wits.
+
 After we've loaded the high part of the core words, we're at
 the "wrapping up" part. We add what we call a "hook word" (an
 empty word with a single letter name) which doesn't cost us
@@ -7,9 +12,5 @@ CURRENT, which PC yields. That is why we write it to the
 LATEST field of the stable ABI: This value will be used at
 boot.
 
-After the last word of the dictionary comes the "source init"
-part. The boot sequence is designed to interpret whatever comes
-after LATEST as Forth source, and this, until it reads ASCII
-EOT character (4). This is generally used for driver init.
 
-Good luck!
+                                                        (cont.)

blk/427

@@ -0,0 +1,6 @@
+After the last word of the dictionary comes the "source init"
+part. The boot sequence is designed to interpret whatever comes
+after LATEST as Forth source, and this, until it reads ASCII
+EOT character (4). This is generally used for driver init.
+
+Good luck!

blk/618

@@ -1,5 +1,6 @@
-0x8000 CONSTANT SYSVARS
 0xff00 CONSTANT RS_ADDR        0xfffa CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0x8000 CONSTANT HERESTART
 4      CONSTANT SDC_SPI
 5      CONSTANT SDC_CSLOW      6      CONSTANT SDC_CSHIGH
 582 LOAD  ( acia decl )

cvm/vm.c

@@ -242,15 +242,6 @@ static void native(NativeWord func) {
     vm.nativew[vm.nativew_count++] = func;
 }
 
-/* INITIAL BOOTSTRAP PLAN
-
-For the initial bootstrap of the C VM, we treat every native word as a stable
-word, giving it exactly the same memory offset as we have in the z80 forth.bin.
-This will greatly simplify the initial bootstrap because we'll be able to
-directly plug the "core words" part of forth.bin into our C VM and run it.
-Once we have that, we can de-stabilize the native words that aren't part of the
-stable ABI and bootstrap ourselves from ourselves. Good plan, right?
-*/
 VM* VM_init() {
     fprintf(stderr, "Using blkfs %s\n", BLKFS_PATH);
     blkfp = fopen(BLKFS_PATH, "r+");

cvm/vm.h

@@ -3,7 +3,7 @@
 
 #define SP_ADDR 0xffff
 #define RS_ADDR 0xff00
-#define SYSVARS 0xe800
+#define SYSVARS RS_ADDR-0x80
 
 typedef uint8_t byte;
 typedef uint16_t word;

cvm/xcomp.fs

@@ -1,6 +1,7 @@
-0xe800 CONSTANT SYSVARS
 0xff00 CONSTANT RS_ADDR
 0xfffa CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0 CONSTANT HERESTART
 : CODE ( natidx -- ) (entry) 0 C, C, ;
 VARIABLE ORG
 CREATE BIN( 0 ,
@@ -95,7 +96,6 @@ ORG @ 0xce + HERE !
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
-," CURRENT @ HERE ! "
 ," BLK$ "
 ," ' EFS@ BLK@* ! "
 ," ' EFS! BLK!* ! "

emul/xcomp.fs

@@ -1,6 +1,7 @@
-0xe800 CONSTANT SYSVARS
 0xff00 CONSTANT RS_ADDR
 0xfffa CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0 CONSTANT HERESTART
 212 LOAD  ( z80 assembler )
 262 LOAD  ( xcomp )
 282 LOAD  ( boot.z80.decl )
@@ -26,7 +27,6 @@
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
-," CURRENT @ HERE ! "
 ," BLK$ "
 ," ' EFS@ BLK@* ! "
 ," ' EFS! BLK!* ! "

recipes/sms/xcomp.fs

@@ -1,8 +1,9 @@
 ( 8K of onboard RAM )
-0xc000 CONSTANT SYSVARS
 0xdd00 CONSTANT RS_ADDR
 ( Memory register at the end of RAM. Must not overwrite )
 0xddca CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0xc000 CONSTANT HERESTART
 SYSVARS 0x70 + CONSTANT VDP_MEM
 0xbf   CONSTANT VDP_CTLPORT
 0xbe   CONSTANT VDP_DATAPORT

recipes/ti84/xcomp.fs

@@ -1,6 +1,7 @@
-0x8000 CONSTANT SYSVARS
 0xbf00 CONSTANT RS_ADDR
 0xbffa CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT SYSVARS
+0x8000 CONSTANT HERESTART
 SYSVARS 0x70 + CONSTANT LCD_MEM
 SYSVARS 0x72 + CONSTANT KBD_MEM
 0x01 CONSTANT KBD_PORT

recipes/trs80/xcomp.fs

@@ -1,6 +1,7 @@
 0xff00 CONSTANT RS_ADDR
 0xfffa CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
+0 CONSTANT HERESTART
 212 LOAD ( z80 assembler )
 262 LOAD ( xcomp )
 282 LOAD ( boot.z80.decl )
@@ -13,7 +14,6 @@ RS_ADDR 0x80 - CONSTANT SYSVARS
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
-," CURRENT @ HERE ! "
 ( 0x0a == NLPTR. TRS-80 wants CR-only newlines )
 ," ' CR 0x0a RAM+ ! BLK$ FD$ " EOT,
 ORG @ 256 /MOD 2 PC! 2 PC!

recipes/z80mbc2/xcomp.fs

@@ -1,5 +1,6 @@
 0xff00 CONSTANT RS_ADDR        0xfffa CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
+0 CONSTANT HERESTART
 212 LOAD  ( z80 assembler )
 262 LOAD  ( xcomp )
 282 LOAD  ( boot.z80.decl )
@@ -37,6 +38,6 @@ CODE (key)
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
-," CURRENT @ HERE ! BLK$ FD$ ' FD@ BLK@* ! ' FD! BLK!* ! " EOT,
+," BLK$ FD$ ' FD@ BLK@* ! ' FD! BLK!* ! " EOT,
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!