.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
+ .define UART_BASE, 0x1000
+ .define UART_STATUS, UART_BASE+0x4
+ .define UART_RECV, UART_BASE+0x8
+ .define UART_TRANS, UART_BASE+0xC
+ .define UART_BAUD, UART_BASE+0x10
+
+ .define UART_TRANS_EMPTY, 0
+ .define UART_RECV_NEW, 1
+
+ .define TIMEOUT_START, 0x13371337
+ .define DEFAULT_PROG_START, 0x200
+ .define STACKSTART, 0x500 ; FIXME
;-----
main:
; setup stackframe
ldil r15, STACKSTART@lo
ldih r15, STACKSTART@hi
+ movst r15
ldil r3, TIMEOUT_START@lo
ldih r3, TIMEOUT_START@hi
ldih r3, UART_STATUS@hi
ldw r3, 0(r3)
andi r3, r3, 1 << UART_RECV_NEW
- jumpzs+ next; jump if zero
+ branchzs+ next; branch if zero
- branch recv_byte
+ call recv_byte
; we received the enter bootrom sign
cmp r0, 0x48 ; 'H'
- jumpeq- bt_H
+ brancheq- bt_H
next:
subi r3, r3, 1
- jumpnz+ timeout_loop
+ branchnz+ timeout_loop
- ; branch to default entry point
+ ; call to default entry point
ldil r0, DEFAULT_PROG_START@lo
ldih r0, DEFAULT_PROG_START@hi
- jumpreg r0
+ branchreg r0
;-----
send_byte:
ldih r3, UART_STATUS@hi
ldw r3, 0(r3)
andi r3, r3, 1 << UART_TRANS_EMPTY
- jumpzs+ send_byte ; jump if zero
+ branchzs+ send_byte ; branch if zero
ldil r3, UART_TRANS@lo
ldih r3, UART_TRANS@hi
- stb r0, 0(r3)
+ stb r1, 0(r3)
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
;-----
ldih r3, UART_STATUS@hi
ldw r3, 0(r3)
andi r3, r3, 1 << UART_RECV_NEW
- jumpzs+ send_byte ; jump if zero
+ branchzs+ send_byte ; branch if zero
ldil r3, UART_RECV@lo
ldih r3, UART_RECV@hi
lwb r0, 0(r3)
;-----
recv_word:
- ldil r1, 0x0
- branch recv_byte
- or r1, r1, r0
+ ldisl r0, 0x0
+ call recv_byte
+ or r0, r0, r1
- branch recv_byte
- sll r0, r0, 8
- or r1, r1, r0
+ call recv_byte
+ sll r1, r1, 8
+ or r0, r0, r1
- branch recv_byte
- sll r0, r0, 16
- or r1, r1, r0
+ call recv_byte
+ sll r1, r1, 16
+ or r0, r0, r1
- branch recv_byte
- sll r0, r0, 24
- or r1, r1, r0
+ call recv_byte
+ sll r1, r1, 24
+ or r0, r0, r1
- addi r0, r1, 0x0
ret
-
;-----
bootrom:
- branch recv_byte
+ call recv_byte
cmpi r0, 0x57 ; 'W'
- jumpeq- bt_W
+ brancheq- bt_W
cmpi r0, 0x52 ; 'R'
- jumpeq- bt_R
+ brancheq- bt_R
cmpi r0, 0x51 ; 'Q'
- jumpeq- bt_Q
+ brancheq- bt_Q
cmpi r0, 0x54 ; 'T'
- jumpeq- bt_T
+ brancheq- bt_T
cmpi r0, 0x4a ; 'J'
- jumpeq- bt_J
+ brancheq- bt_J
; cmpi r0, 0x48 ; 'H'
- ; jumpeq bt_H
+ ; brancheq bt_H
; FALL THROUGH ;)
bt_H:
- ldisl r0, 0x4f ; 'O'
- branch send_byte
- jump bootrom
+ ldisl r1, 0x4f ; 'O'
+ call send_byte
+ branch bootrom
bt_W:
- branch recv_word ; receive addr
- addi r6, r0, 0x0
- branch recv_word ; receive instr
+ call recv_word ; receive addr
+ mov r6, r0
+ call recv_word ; receive instr
stx r0, 0(r6)
- ldisl r0, 0x44 ; 'D'
- branch send_byte
- jump bootrom
+ ldisl r1, 0x44 ; 'D'
+ call send_byte
+ branch 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
+ ldisl r1, 0x46 ; 'F'
+ call send_byte
+ ldx r1, 0(r2)
+ call send_word
+ branch 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
+ ldisl r1, 0x41 ; 'A'
+ call send_byte
+ branch 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
+ ldisl r1, 0x47 ; 'G'
+ call send_byte
+ ldw r1, 0(r2)
+ call send_word
+ branch bootrom
bt_J:
- branch recv_word
- jumpreg r0
+ call recv_word
+ branchreg r0
-; 101 instr. please update after modification
+; 102 instr. please update after modification
projects / calu.git / blobdiff