progress: new assembler works, instruction set fully implemented with call/ret and push/pop, bf.dsa works which means the dsa assembly language works reliably. still a few bugs to fix. might be able to squeeze out a tiny bit more performance

dsa_resources/print.dsa

@@ -0,0 +1,292 @@
+// lib:
+// print.dsa
+
+// usage:
+//
+// include print "<relative path>"
+//
+// usage for print:
+//      push (register containing address of string)
+//      call print::print
+//
+// usage for reset:
+//      call print::reset
+//
+// usage for clear:
+//      call print::clear
+//
+// usage for print_byte:
+//      push (register containing byte)
+//      call print::print_byte
+//
+// usage for print_word:
+//      push (register containing word)
+//      call print::print_word
+//
+// usage for print_num:
+//      push (register containing number to print in decimal)
+//      call print::print_num
+//
+
+dw display: 0x20000
+dw current: 0x20000
+
+// ------------------------------------------
+// prints the string at addr(arg[0]) to the screen.
+print: func
+
+    ldw bpr, rg0, 8
+    ldw current, rg1
+
+_print_loop:
+    ldb rg0, rg2
+    ieq rg2, zero, rg4
+    jnz rg4, _end
+    stb rg2, rg1
+
+    addi rg0, 1
+    addi rg1, 1
+
+    jmp _print_loop
+// ------------------------------------------
+// println:
+//     push bpr
+//     mov spr, bpr
+
+//     ldw bpr, rg0, 8
+//     ldw current, rg1
+
+// _println_loop:
+//     ldb rg0, acc
+//     ieq acc, zero, rg4
+//     jnz rg4, _println_end
+//     stb acc, rg1
+
+//     addi rg0, 1
+//     addi rg1, 1
+
+//     jmp _println_loop
+
+// _println_end:
+//     call print_newline
+//     jmp _end
+
+// ------------------------------------------
+// prints the value of arg[0] to the screen.
+// print_word:
+//     push bpr
+//     mov spr, bpr
+
+//     ldw bpr, rg0, 8
+//     ldw current, rg1
+
+//     addi rg1, 3
+
+//     stb rg0, rg1
+//     subi rg1, 1
+//     shr rg0, 8
+//     stb rg0, rg1
+//     subi rg1, 1
+//     shr rg0, 8
+//     stb rg0, rg1
+//     subi rg1, 1
+//     shr rg0, 8
+//     stb rg0, rg1
+
+//     addi rg1, 4
+//     jmp _end
+
+// ------------------------------------------
+// prints the last byte of arg[0] to the screen.
+print_byte: func
+    ldw bpr, rg0, 8
+    ldw current, rg1
+
+    stb rg0, rg1
+    addi rg1, 1
+    jmp _end
+
+// ------------------------------------------
+// prints the value of arg[0] to the screen in hex.
+// print_hex_word:
+//     push bpr
+//     mov spr, bpr
+
+//     ldw current, rg1
+
+//     ldb bpr, rg0, 8
+//     push rg0
+//     call _print_hex_byte
+//     addi spr, 4
+
+//     ldb bpr, rg0, 9
+//     push rg0
+//     call _print_hex_byte
+//     addi spr, 4
+
+//     ldb bpr, rg0, 10
+//     push rg0
+//     call _print_hex_byte
+//     addi spr, 4
+
+//     ldb bpr, rg0, 11
+//     push rg0
+//     call _print_hex_byte
+//     addi spr, 4
+
+//     jmp _end
+
+// ------------------------------------------
+// prints the last byte of arg[0] to the screen in hex.
+print_hex_byte: func
+    ldw bpr, rg0, 8
+    ldw current, rg1
+
+    call _print_hex_byte
+    jmp _end
+
+// function body
+_print_hex_byte:
+    lli 0xF, rg2
+    push rg0
+
+    shr rg0, 4
+    and rg0, rg2, rg0
+    call _print_hex_nibble
+    pop rg0
+
+    and rg0, rg2, rg0
+    call _print_hex_nibble
+    ret
+
+// print a hex digit
+_print_hex_nibble:
+    lli 10, rg3
+    ilt rg0, rg3, rg4
+    jnz rg4, _print_hex_nibble_number
+    addi rg0, 0x37, rg0
+    stb rg0, rg1
+    addi rg1, 1
+    ret
+
+// helper function.
+_print_hex_nibble_number:
+    addi rg0, 0x30, rg0
+    stb rg0, rg1
+    addi rg1, 1
+    ret
+
+// ------------------------------------------
+// print whitespace
+print_whitespace: func
+    ldw current, rg1
+    lli 0x20, rg0
+    stb rg0, rg1
+    addi rg1, 1
+    jmp _end
+
+// // ------------------------------------------
+// // print newline
+// print_newline:
+//     push bpr
+//     mov spr, bpr
+
+//     ldw display, rg0
+//     ldw current, rg1
+
+//     sub rg1, rg0, rg0
+
+//     lwi 80, rg2
+//     push rg0
+//     push rg1
+//     push rg2
+//     push rg0
+//     push rg2
+//     call maths::divmod
+//     pop zero   // result
+//     pop rg3    // remainder
+//     pop rg0
+//     pop rg1
+//     pop rg2
+
+//     sub rg1, rg3, rg2
+//     addi rg2, 80, rg1
+
+//     jmp _end
+
+// ------------------------------------------
+// prints arg[0] as a decimal number to the screen.
+// print_num:
+//     push bpr
+//     mov spr, bpr
+
+//     ldw bpr, rg0, 8
+//     lli 0, rg5
+
+//     ieq rg0, zero, rg4
+//     jez rg4, _print_num_extract_digits
+
+//     lli 0x30, rg6
+//     push rg6
+//     lli 1, rg5
+//     jmp _print_num_output
+
+// _print_num_extract_digits:
+//     ieq rg0, zero, rg4
+//     jnz rg4, _print_num_output
+
+//     push rg0
+//     lli 10, rg1
+//     push rg1
+//     call maths::divmod
+//     pop rg0   // quotient
+//     pop rg1   // remainder
+
+//     addi rg1, 0x30, rg6
+//     push rg6
+//     inc rg5
+
+//     jmp _print_num_extract_digits
+
+// _print_num_output:
+//     ldw current, rg1
+
+// _print_num_output_loop:
+//     ieq rg5, zero, rg4
+//     jnz rg4, _print_num_done
+
+//     pop rg6
+//     stb rg6, rg1
+//     addi rg1, 1
+//     dec rg5
+
+//     jmp _print_num_output_loop
+
+// _print_num_done:
+//     jmp _end
+
+// ------------------------------------------
+// resets the cursor position to 0x20000 (0,0)
+reset: func
+    ldw display, rg1
+    jmp _end
+
+// ------------------------------------------
+// clears the screen
+clear: func
+    lli 500, rg0
+    ldw display, rg1
+
+_clear_loop:
+    subi rg0, 1, rg0
+    stw zero, rg1
+    addi rg1, 4
+    igt rg0, zero, rg4
+    jnz rg4, _clear_loop
+    jmp _end
+
+// ------------------------------------------
+// return — saves current, restores frame, returns
+_end:
+    stw rg1, current
+    return