.data
.text
- ; r0 .. param0
- ; r1 .. param1
- ; r2 .. param2
- ; r15 .. stackpointer
- ; r0 .. return
-
- ; TODO: will the assembler be able to evaluate these expressions?
- UART_BASE=0x1000
- UART_STATUS=(UART_BASE+0x4)
- UART_RECV=(UART_BASE+0x8)
- UART_TRANS=(UART_BASE+0xC)
- UART_BAUD=(UART_BAUD+0x10)
-
- UART_TRANS_EMPTY=0
- UART_RECV_NEW=1
-
- TIMEOUT_START=0x13371337
- DEFAULT_PROG_START=0x200
- STACKSTART=0x500 ; FIXME
-;-----
-main:
- ; setup stackframe
- ldil r15, STACKSTART@lo
- ldih r15, STACKSTART@hi
+ .define UART_BASE, 0x2000
+ .define UART_STATUS, 0x0
+ .define UART_RECV, 0xc
+ .define UART_TRANS, 0x8
- ldil r3, TIMEOUT_START@lo
- ldih r3, TIMEOUT_START@hi
+ .define UART_TRANS_EMPTY, 0x1
+ .define UART_RECV_NEW, 0x2
-timeout_loop:
- ldil r3, UART_STATUS@lo
- ldih r3, UART_STATUS@hi
- ldw r3, 0(r3)
- andi r3, r3, 1 << UART_RECV_NEW
- jumpzs+ next; jump if zero
+ .define PBASE, 0x2030
+ .define PADDR, 0x4
+ .define PDATA, 0x8
- branch recv_byte
- ; we received the enter bootrom sign
- cmp r0, 0x48 ; 'H'
- jumpeq- bt_H
-
-next:
- subi r3, r3, 1
- jumpnz+ timeout_loop
+;-----
+start:
+ br+ main
+ br+ main
+ ret
- ; branch to default entry point
- ldil r0, DEFAULT_PROG_START@lo
- ldih r0, DEFAULT_PROG_START@hi
- jumpreg r0
+main:
+ ldi r10, UART_BASE@lo
+ 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
+
+ call recv_byte
+ ; we received the enter bootrom sign
+ xor r1, r1, r1
+ cmpi r0, 0x48 ; 'H'
+ breq- bt_H
+ br poll ; else
;-----
send_byte:
- ldil r3, UART_STATUS@lo
- ldih r3, UART_STATUS@hi
- ldw r3, 0(r3)
- andi r3, r3, 1 << UART_TRANS_EMPTY
- jumpzs+ send_byte ; jump if zero
- ldil r3, UART_TRANS@lo
- ldih r3, UART_TRANS@hi
- stb r0, 0(r3)
+ ldw r3, UART_STATUS(r10)
+ andx r3, UART_TRANS_EMPTY
+ brnz+ send_byte ; branch if not zero
+ stb r1, UART_TRANS(r10)
ret
;-----
send_word:
- ; TODO: loop? (less codesize...)
- branch send_byte
- lrs r0, r0, 8
- branch send_byte
- lrs r0, r0, 8
- branch send_byte
- lrs r0, r0, 8
- branch send_byte
+ lrs r0, r1, 0
+ call send_byte
+ lrs r0, r1, 8
+ call send_byte
+ lrs r0, r1, 16
+ call send_byte
+ lrs r0, r1, 24
+ call send_byte
ret
;-----
recv_byte:
- ldil r3, UART_STATUS@lo
- ldih r3, UART_STATUS@hi
- ldw r3, 0(r3)
- andi r3, r3, 1 << UART_RECV_NEW
- jumpzs+ send_byte ; jump if zero
- ldil r3, UART_RECV@lo
- ldih r3, UART_RECV@hi
- lwb r0, 0(r3)
+ 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)
ret
;-----
recv_word:
- ldil r1, 0x0
- branch recv_byte
- or r1, r1, r0
+ xor r1, r1, r1
+ call recv_byte
+ or r1, r0, r1
- branch recv_byte
- sll r0, r0, 8
- or r1, r1, r0
+ call recv_byte
+ lls r1, r1, 8
+ or r1, r0, r1
- branch recv_byte
- sll r0, r0, 16
- or r1, r1, r0
+ call recv_byte
+ lls r1, r1, 8
+ or r1, r0, r1
- branch recv_byte
- sll r0, r0, 24
- or r1, r1, r0
+ call recv_byte
+ lls r1, r1, 8
+ or r1, r0, r1
- addi r0, r1, 0x0
+ addi r0, r1, 0
ret
-
;-----
bootrom:
- branch recv_byte
+ call recv_byte
+ br tehend
+ xor r1, r1, r1
cmpi r0, 0x57 ; 'W'
- jumpeq- bt_W
+ breq- bt_W
cmpi r0, 0x52 ; 'R'
- jumpeq- bt_R
+ breq- bt_R
cmpi r0, 0x51 ; 'Q'
- jumpeq- bt_Q
+ breq- bt_Q
cmpi r0, 0x54 ; 'T'
- jumpeq- bt_T
+ breq- bt_T
cmpi r0, 0x4a ; 'J'
- jumpeq- bt_J
+ breq- bt_J
; cmpi r0, 0x48 ; 'H'
- ; jumpeq bt_H
+ ; breq bt_H
; FALL THROUGH ;)
bt_H:
- ldisl r0, 0x4f ; 'O'
- branch send_byte
- jump bootrom
+ ldi r1, 0x4f ; 'O'
+ call send_byte
+ call send_byte
+ br bootrom
bt_W:
- branch recv_word ; receive addr
- addi r6, r0, 0x0
- branch recv_word ; receive instr
- stx r0, 0(r6)
- ldisl r0, 0x44 ; 'D'
- branch send_byte
- jump bootrom
+ call recv_word ; receive addr
+ stw r0, PADDR(r11)
+ call recv_word ; receive instr
+ stw r0, PDATA(r11)
+ ldi r1, 0x44 ; 'D'
+ call send_byte
+ br bootrom
bt_R:
- branch recv_word ; receive addr
- ldx r1, 0(r0)
- ldisl r0, 0x46 ; 'F'
- branch send_byte
- addi r0, r1, 0x0
- branch send_word
- jump bootrom
+ call recv_word ; receive addr
+ mov r2, r0
+ ldi r1, 0x46 ; 'F'
+ call send_byte
+ ldx r1, 0(r2)
+ call send_word
+ br bootrom
bt_Q:
- branch recv_word ; receive addr
- addi r6, r0, 0x0
- branch recv_word ; receive data
+ call recv_word ; receive addr
+ mov r6, r0
+ call recv_word ; receive data
stw r0, 0(r6)
- ldisl r0, 0x41 ; 'A'
- branch send_byte
- jump bootrom
+ ldi r1, 0x41 ; 'A'
+ call send_byte
+ br bootrom
bt_T:
- branch recv_word ; receive addr
- ldw r1, 0(r0)
- ldisl r0, 0x47 ; 'G'
- branch send_byte
- addi r0, r1, 0x0
- branch send_word
- jump bootrom
+ call recv_word ; receive addr
+ mov r2, r0
+ ldi r1, 0x47 ; 'G'
+ call send_byte
+ ldw r1, 0(r2)
+ call send_word
+ br bootrom
bt_J:
- branch recv_word
- jumpreg r0
+ call recv_word
+ brr r0
-; 101 instr. please update after modification
+tehend:
projects / calu.git / blobdiff