From c77469e1a1b7ba90c7013ee37b6c8c120f905435 Mon Sep 17 00:00:00 2001
From: Joppe Blondel <joppe@joppeb.nl>
Date: Wed, 7 Oct 2026 15:29:26 +0200
Subject: [PATCH] Added bios flush and simple hello command

---
 apps/basic/basic.asm | 31 +++++++++++++++++++++++++++----
 bios.asm             | 12 ++++++++++++
 bios.inc             |  1 +
 3 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/apps/basic/basic.asm b/apps/basic/basic.asm
index 9244bbb..71cdd99 100644
--- a/apps/basic/basic.asm
+++ b/apps/basic/basic.asm
@@ -43,8 +43,8 @@
 MC_BIOS_PUTC            .EQU    BIOS_PUTC
 MC_BIOS_TRY_GETC        .EQU    BIOS_TRY_GETC
 MC_BIOS_GETC            .EQU    BIOS_GETC
-MC_BIOS_FLUSH           .EQU    00000H
-MC_BIOS_MONITOR         .EQU    00000H
+MC_BIOS_FLUSH           .EQU    BIOS_FLUSH
+MC_BIOS_MONITOR         .EQU    BIOS_RAM_START
 MC_CODE_START           .EQU    BASIC_RAM_START
 MC_RAM_START            .EQU    BASIC_RAM_START + BASIC_ROM_SIZE
 MC_RAM_END              .EQU    0FFFFH
@@ -377,6 +377,7 @@ WORDS:  .BYTE   'E'+80H,"ND"
         .BYTE   'L'+80H,"EFT$"
         .BYTE   'R'+80H,"IGHT$"
         .BYTE   'M'+80H,"ID$"
+        .BYTE   'H'+80H,"ELLO"
         .BYTE   80H             ; End of list marker
 
 ; KEYWORD ADDRESS TABLE
@@ -449,6 +450,7 @@ ZLTH    .EQU    0B5H            ; <
 ZSGN    .EQU    0B6H            ; SGN
 ZPOINT  .EQU    0C7H            ; POINT
 ZLEFT   .EQU    0CDH +2         ; LEFT$
+ZHELLO  .EQU    0D2H
 
 ; ARITHMETIC PRECEDENCE TABLE
 
@@ -1252,7 +1254,19 @@ EXCUTE: CALL    GETCHR          ; Get key word
         LD      DE,RUNCNT       ; Where to RETurn to
         PUSH    DE              ; Save for RETurn
 IFJMP:  RET     Z               ; Go to RUNCNT if end of STMT
-ONJMP:  SUB     ZEND            ; Is it a token?
+;ONJMP:  SUB     ZEND            ; Is it a token?
+ONJMP:
+        ; Own commands
+        ; ------------
+CHKHELLO:  
+        CP      ZHELLO
+        JP      NZ,STDONJMP
+        ld      BC,HELLO
+        PUSH    BC
+        jp      GETCHR
+        ; ------------
+STDONJMP:  
+        SUB     ZEND            ; Is it a token?
         JP      C,LET           ; No - try to assign it
         CP      ZNEW+1-ZEND     ; END to NEW ?
         JP      NC,SNERR        ; Not a key word - ?SN Error
@@ -4364,7 +4378,7 @@ JJUMP1: LD      IX,-1           ; Flag cold start
 MONOUT: JP      MC_BIOS_PUTC    ; output a char
 
 
-MONITR: ;CALL    MC_BIOS_FLUSH
+MONITR: CALL    MC_BIOS_FLUSH
         JP      MC_BIOS_MONITOR ; Restart (Normally Monitor Start)
 
 
@@ -4385,5 +4399,14 @@ TSTBIT: PUSH    AF              ; Save bit mask
 OUTNCR: CALL    OUTC            ; Output character in A
         JP      PRNTCRLF        ; Output CRLF
 
+HELLO:
+        RET     NZ
+        PUSH    HL
+        LD      HL,HELLOMSG
+        CALL    PRS
+        POP     HL
+        RET
+HELLOMSG: .asciz "Hello!"
+
 .end
 
diff --git a/bios.asm b/bios.asm
index 0f4c708..b15f732 100644
--- a/bios.asm
+++ b/bios.asm
@@ -92,6 +92,8 @@ boot_copy:
     jp          try_getc
 .org BIOS_PUTS
     jp          puts
+.org BIOS_FLUSH
+    jp          flush
 
 ; -------------------------------------------------------
 ; BIOS ENTRY
@@ -435,12 +437,22 @@ puts:
 
 ; -------------------------------------------------------
 ; Get a byte, block if unavailable
+; returns a (byte)
 ; -------------------------------------------------------
 getc:
     call        try_getc
     jr          c,getc
     ret
 
+; -------------------------------------------------------
+; Wait till full tx buffer is empty
+; uses a
+; -------------------------------------------------------
+flush:
+    ld          a,(TX_COUNT)
+    cp          0
+    jr          nz,flush
+
 ; -------------------------------------------------------
 ; Strings
 ; -------------------------------------------------------
diff --git a/bios.inc b/bios.inc
index 04bed92..5b34ce3 100644
--- a/bios.inc
+++ b/bios.inc
@@ -2,3 +2,4 @@ BIOS_PUTC               .equ 0c050h
 BIOS_GETC               .equ 0c053h
 BIOS_TRY_GETC           .equ 0c056h
 BIOS_PUTS               .equ 0c059h
+BIOS_FLUSH              .equ 0c05ch