Merge pull request #21 from davidgiven/basic

Fix some how-could-this-ever-have-worked issues with BBC BASIC.
davidgiven · Feb 11, 2020 · cbcd2c2 · cbcd2c2
2 parents dbdd4a4 + 394a13e
commit cbcd2c2
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Showing 4 changed files with 66 additions and 59 deletions.
diff --git a/third_party/bbcbasic/build.lua b/third_party/bbcbasic/build.lua
@@ -11,7 +11,8 @@ for _, f in pairs(srcs) do
 end
 
 ld80 {
-    name = "bbcbasic_img",
+    name = "bbcbasic",
+	address = 0x100,
     srcs = {
         "+patch",
         "-P0200",
@@ -26,7 +27,3 @@ ld80 {
     }
 }
 
-bintocom {
-    name = "bbcbasic",
-    srcs = { "+bbcbasic_img" }
-}
diff --git a/third_party/bbcbasic/cmos.z80 b/third_party/bbcbasic/cmos.z80
@@ -1078,6 +1078,7 @@ OSINIT: LD      C,45            ;*
 ;        JP      PE,SUM
 ;        OR      E
 ;        JR      NZ,BADSUM
+		XOR     A
         LD      B,INILEN
         LD      HL,TABLE
 CLRTAB: LD      (HL),A          ;CLEAR FILE TABLE ETC.
@@ -1473,4 +1474,4 @@ OPTVAL: DEFB    0
 INILEN  EQU     $-TABLE
 ;
 FIN:    END
-
+
diff --git a/third_party/bbcbasic/exec.z80 b/third_party/bbcbasic/exec.z80
@@ -206,8 +206,13 @@ CHAIN0: LD      SP,(HIMEM)
         CALL    LOAD0
 RUN0:   LD      SP,(HIMEM)      ;PREPARE FOR RUN
         LD      IX,RANDOM
-RAND:   LD      A,R             ;RANDOMISE (CARE!)
-        JR      Z,RAND
+		; dtrg: bugfix here; on emulators, R is always zero, and the original
+		; code always waiting until it was non-zero, resulting in a hang.
+		; Instead we crudely hack around it.
+		ld      a, r
+		jr      nz, .1
+		inc     a
+.1
         RLCA
         RLCA
         LD      (IX+3),A
@@ -2864,4 +2869,4 @@ LF      EQU     0AH
 CR      EQU     0DH
 ;
 FIN:    END
-
+
diff --git a/third_party/bbcbasic/patch.z80 b/third_party/bbcbasic/patch.z80
@@ -65,7 +65,7 @@ INIT:   ;CALL    INTIME          ;INITIALISE TIMER
 ;REBOOT - Stop interrupts and return to CP/M. 
 ;
 REBOOT: LD      A,3
-        OUT     (CTC0+3),A
+;        OUT     (CTC0+3),A
         RST     0
 
 ;
@@ -173,60 +173,64 @@ WAIT1:  CP      (HL)
 ; Destroys: A,D,E,H,L,F
 ;
 ;
-PCSR:   LD      A,E
-        ADD     HL,HL
-        ADD     HL,HL
-        ADD     HL,HL
-        ADD     HL,HL           ;*16
-        LD      D,H
-        LD      E,L
-        ADD     HL,HL
-        ADD     HL,HL
-        ADD     HL,DE           ;*80
-        LD      D,0
-        LD      E,A
-        ADD     HL,DE           ;OFFSET FROM HOME
-        LD      DE,(HOME)
-        ADD     HL,DE
-        LD      A,14
-        OUT     (CRTCS),A
-        LD      A,H
-        AND     0FH
-        OUT     (CRTCD),A
-        LD      A,15
-        OUT     (CRTCS),A
-        LD      A,L
-        OUT     (CRTCD),A
-        RET
+PCSR:   RET
+;		LD      A,E
+;        ADD     HL,HL
+;        ADD     HL,HL
+;        ADD     HL,HL
+;        ADD     HL,HL           ;*16
+;        LD      D,H
+;        LD      E,L
+;        ADD     HL,HL
+;        ADD     HL,HL
+;        ADD     HL,DE           ;*80
+;        LD      D,0
+;        LD      E,A
+;        ADD     HL,DE           ;OFFSET FROM HOME
+;        LD      DE,(HOME)
+;        ADD     HL,DE
+;        LD      A,14
+;        OUT     (CRTCS),A
+;        LD      A,H
+;        AND     0FH
+;        OUT     (CRTCD),A
+;        LD      A,15
+;        OUT     (CRTCS),A
+;        LD      A,L
+;        OUT     (CRTCD),A
+;        RET
 ;
 ;GCSR - Return cursor coordinates.
 ;   Outputs:  DE = X coordinate (POS)
 ;             HL = Y coordinate (VPOS)
 ;  Destroys: A,D,E,H,L,F
 ;
-GCSR:   LD      A,14
-        OUT     (CRTCS),A
-        IN      A,(CRTCD)
-        LD      H,A
-        LD      A,15
-        OUT     (CRTCS),A
-        IN      A,(CRTCD)
-        LD      L,A
-        LD      DE,(HOME)
-        SBC     HL,DE
-        LD      A,H
-        AND     7
-        LD      H,A
-        LD      DE,-80
-        LD      A,D
-ROWS:   ADD     HL,DE
-        INC     A
-        JR      C,ROWS
-        SBC     HL,DE
-        LD      D,0
-        LD      E,A
-        EX      DE,HL
-        RET
+GCSR:	ld		de, 0
+		ld 		hl, 0
+		ret
+;		LD      A,14
+;        OUT     (CRTCS),A
+;        IN      A,(CRTCD)
+;        LD      H,A
+;        LD      A,15
+;        OUT     (CRTCS),A
+;        IN      A,(CRTCD)
+;        LD      L,A
+;        LD      DE,(HOME)
+;        SBC     HL,DE
+;        LD      A,H
+;        AND     7
+;        LD      H,A
+;        LD      DE,-80
+;        LD      A,D
+;ROWS:   ADD     HL,DE
+;        INC     A
+;        JR      C,ROWS
+;        SBC     HL,DE
+;        LD      D,0
+;        LD      E,A
+;        EX      DE,HL
+;        RET
 ;
 TIME:   DEFS    4
 ;
@@ -256,4 +260,4 @@ CRTCD   EQU     85H
         DEFB    'A' AND 1FH     ;INSERT CHARACTER
 ;
 FIN:    END
-
+