- Implemented the multiply expression into the assembler.

- Implemented support for the SIB addressing mode into
  the assembler.

  SIB is short for "Scale Index, and Base", and works
  much like x86's version of SIB (scale*index+base),
  although my version supports any scale value between
  1, and 256.

- Redid the line shifting routine in SuBEditor.

  It now uses memcpy, and memset to do that, and also
  supports shifting the line left, or right by any
  number of characters.

1 files changed, 67 insertions, 24 deletions

diff --git a/programs/sub-suite/libc.s b/programs/sub-suite/libc.s
index 53e936a..b34d2d3 100644
--- a/programs/sub-suite/libc.s
+++ b/programs/sub-suite/libc.s
@@ -187,7 +187,7 @@ toupper:
 ; Input: D = size in bytes to allocate.
 ; Output: A = Pointer to allocated memory.
 ; Caller preserved registers: D.
-; Callie preserved registers: B, X, Y.
+; Callee preserved registers: B, X, Y.
 
 malloc:
 	phb.q			; Preserve B.
@@ -272,7 +272,7 @@ malloc:
 ; Input: D = Pointer to allocated memory.
 ; Output: none.
 ; Caller preserved registers: D.
-; Callie preserved registers: A, B, X, Y, E.
+; Callee preserved registers: A, B, X, Y, E.
 
 free:
 	pha.q			; Preserve A.
@@ -405,31 +405,74 @@ free:
 	pla.q			; Restore A.
 	rts			; End of free.
 
-
 ; memcpy: memory to memory copy.
-; Input: A = Destination pointer. B = Source pointer. Y = Number of bytes to copy.
+; Input: D = Destination pointer. S = Source pointer. F = Number of bytes to copy.
 ; Output: A = Destination pointer.
-; Caller preserved registers: none.
-; Callie preserved registers: none.
+; Caller preserved registers: D, S, F.
+; Callee preserved registers: B.
 
 memcpy:
-	pha.q		; Preserve the return value.
-	pha.q		; Push the destination pointer on the stack.
-	phb.q		; Push the source pointer on the stack.
-	phy.q		; Push the size on the stack.
-	and #0		; Reset A.
-	tab		; Reset B.
-	cpy #0		; Is the size zero?
-	beq @end	; Yes, so we're done.
+	phb.q			; Preserve B.
+	xor b, b		; Reset B.
+	mov a, d		; Set the return value to the destination pointer.
+	cmp f, #0		; Is the size zero?
+	beq @end		; Yes, so we're done.
 @loop:
-	lda (sp+9)	; Get a byte from the source.
-	sta (sp+17)	; Copy it to the destination.
-	inc.q sp+9	; Increment the source pointer.
-	inc.q sp+17	; Increment the destination pointer.
-	dey		; Decrement the size.
-	beq @end	; The size is zero, so we're done.
-	bra @loop	; Keep looping.
+	mov (d+b), (s+b)	; Copy a byte from the source, into the destination.
+	inb			; Increment the counter.
+	cmp b, f		; Is the counter the same as the size?
+	bne @loop		; No, so keep looping.
+@end:
+	plb.q			; Restore B.
+	rts			; End of memcpy.
+
+
+; memset: Set memory to some value.
+; Input: D = Destination pointer. S = Constant value. F = Number of bytes to set.
+; Output: A = Destination pointer.
+; Caller preserved registers: D, S, F.
+; Callee preserved registers: B.
+
+memset:
+	phb.q			; Preserve B.
+	xor b, b		; Reset B.
+	mov a, d		; Set the return value to the destination pointer.
+	cmp f, #0		; Is the size zero?
+	beq @end		; Yes, so we're done.
+@loop:
+	mov (d+b), s		; Set the destination byte, to the constant value.
+	inb			; Increment the counter.
+	cmp b, f		; Is the counter the same as the size?
+	bne @loop		; No, so keep looping.
+@end:
+	plb.q			; Restore B.
+	rts			; End of memset.
+
+
+; max: Get the largest of two integers.
+; Input: D = First value, S = Second value.
+; Output: A = Largest of the two values.
+; Caller preserved registers: D, S.
+; Callee preserved registers: None.
+
+max:
+	mov a, s		; Set the return value to the second value.
+	cmp d, s		; Is the first value greater than the second value?
+	beq @end		; No, so we're done.
+	mcs a, d		; Set the return value to the first value if so.
+@end:
+	rts			; End of max.
+
+
+; min: Get the smallest of two integers.
+; Input: D = First value, S = Second value.
+; Output: A = Smallest of the two values.
+; Caller preserved registers: D, S.
+; Callee preserved registers: None.
+
+min:
+	mov a, s		; Set the return value to the second value.
+	cmp d, s		; Is the first value less than the second value?
+	mcc a, d		; Set the return value to the first value if so.
 @end:
-	ads #$18	; Clean up the stack frame.
-	pla.q		; Restore the return value.
-	rts		; End of memcpy.
+	rts			; End of min.