added serial-out support to emulator + serial lib & command line mode for dsa emulator

2026-02-23 19:51:05 +00:00
parent 7ab1ac8842
commit 1d38aca523
22 changed files with 1906 additions and 24 deletions
@@ -0,0 +1,105 @@
+
+// multiply.dsa
+// usage:
+//
+// include multiply "<relative path>"
+//
+// usage for multiply:
+// push (arg1)
+// push (arg0)
+// call multiply::multiply
+// pop (arg0)
+// pop (arg1)
+
+multiply:
+    push bpr
+    mov spr, bpr
+
+    ldw bpr, rg0, 8  // load op 2
+    ldw bpr, rg1, 12 // load op 1
+    lwi 0, rg2       // initialise rg2 to zero
+
+_multiply_loop:
+    add rg2, rg0, rg2
+    dec rg1
+
+    cmp rg1, zero
+    jgt _multiply_loop
+
+_multiply_end:
+    stw rg2, bpr, 8
+
+    mov bpr, spr
+    pop bpr
+    return
+
+divmod:
+    push bpr
+    mov spr, bpr
+
+    ldw bpr, rg1, 8  // load op 2
+    ldw bpr, rg0, 12 // load op 1
+
+    lli 0, rg3
+
+_divmod_loop:
+    cmp rg0, rg1
+    jlt _divmod_end
+
+    sub rg0, rg1, rg0
+    inc rg3
+
+    jmp _divmod_loop
+
+_divmod_end:
+    // store div in first arg
+    // store mod in second arg
+    stw rg3, bpr, 8
+    stw rg0, bpr, 12
+
+    mov bpr, spr
+    pop bpr
+    return
+
+// multiply.dsa - improved version
+// Multiplies two 32-bit numbers using shift-and-add
+//
+// Usage:
+// push operand2  (multiplier)
+// push operand1  (multiplicand)
+// call multiply::multiply
+// pop result
+// pop zero       (discard second argument)
+
+new_multiply:
+    push bpr
+    mov spr, bpr
+
+    ldw bpr, rg0, 8     // rg0 = multiplicand
+    ldw bpr, rg1, 12    // rg1 = multiplier
+
+    lli 0, rg2          // rg2 = result (accumulator)
+    lli 32, rg3         // rg3 = bit counter
+
+mult_loop:
+    // Check if lowest bit of multiplier is 1
+    lli 1, acc
+    and rg1, acc, acc   // acc = rg1 & 1
+    cmp acc, zero
+    jeq skip_add        // if (rg1 & 1) == 0, skip addition
+
+    // Add multiplicand to result
+    add rg2, rg0, rg2
+
+skip_add:
+    shl rg0, 1          // shift multiplicand left
+    shr rg1, 1          // shift multiplier right
+
+    dec rg3
+    cmp rg3, zero
+    jgt mult_loop
+
+    stw rg2, bpr, 8     // store result
+    mov bpr, spr
+    pop bpr
+    return