bootromfun: geht noch immmer...

[calu.git] / 2_isa / src / bootrom.s

diff --git a/2_isa/src/bootrom.s b/2_isa/src/bootrom.s
index 18bc1ca4dc54cfb2cbc2cbcd35611d31207e9bd7..d38e1854527f517791893b82811e21e057a93780 100644 (file)
--- a/2_isa/src/bootrom.s
+++ b/2_isa/src/bootrom.s
@@ -24,24 +24,20 @@ main:
        ldih r10, UART_BASE@hi
        ldi r11, PBASE@lo
        ldih r11, PBASE@hi
-;poll:
-;      ldw r3, UART_STATUS(r10)
-;      andx r3, UART_RECV_NEW
-;      brzs+ poll; branch if zero
-
+poll:
        call recv_byte
        ; we received the enter bootrom sign
+       xor r1, r1, r1
        cmpi r0, 0x48 ; 'H'
-       xor r1, r1, r1 ; TODO: wieder raufziehen
-       breq- bt_H
-       ; br poll ; else
+       breq+ bt_H
+       br poll ; else
 
 ;-----
 send_byte:
        ldw r3, UART_STATUS(r10)
        andx r3, UART_TRANS_EMPTY
        brnz+ send_byte ; branch if not zero
-       stb r1, UART_TRANS(r10)
+       stw r1, UART_TRANS(r10)
        ret
 
 ;-----
@@ -58,11 +54,11 @@ send_word:
 
 ;-----
 recv_byte:
-;      ldw r3, UART_STATUS(r10)
-;      andx r3, UART_RECV_NEW
-;      brzs+ recv_byte; branch if zero
+       ldw r3, UART_STATUS(r10)
+       andx r3, UART_RECV_NEW
+       brzs+ recv_byte; branch if zero
        xor r0, r0, r0
-;      ldb r0, UART_RECV(r10)
+       ldw r0, UART_RECV(r10)
        ret
 
 ;-----
@@ -89,6 +85,8 @@ recv_word:
 ;-----
 bootrom:
        call recv_byte
+       ldi r1, 0x50 ; 'P'
+       call send_byte
        br tehend
 
        xor r1, r1, r1