Refined the comments in the target start-up files.

Fixed typo errors.  Made the comments consistent across all those files.

libsrc/plus4/crt0.s

@@ -29,7 +29,7 @@ IRQInd          = $500  ; JMP $0000 - used as indirect IRQ vector
 
 Start:
 
-; Save the zero page locations we need
+; Save the zero-page locations that we need.
 
         sei                     ; No interrupts since we're banking out the ROM
         sta     ENABLE_RAM
@@ -41,13 +41,13 @@ L1:     lda     sp,x
         sta     ENABLE_ROM
         cli
 
-; Switch to second charset
+; Switch to the second charset.
 
         lda     #14
         jsr     $FFD2           ; BSOUT
 
-; Save system stuff and setup the stack. The stack starts at the top of the
-; usable RAM.
+; Save some system stuff; and, set up the stack. The stack starts at the top
+; of the usable RAM.
 
         tsx
         stx     spsave          ; save system stk ptr
@@ -57,7 +57,7 @@ L1:     lda     sp,x
         lda     #>(__RAM_START__ + __RAM_SIZE__ + __STACKSIZE__)
         sta     sp+1
 
-; Setup the IRQ vector in the banked RAM and switch off the ROM
+; Set up the IRQ vector in the banked RAM; and, switch off the ROM.
 
         ldx     #<IRQ
         ldy     #>IRQ
@@ -67,35 +67,35 @@ L1:     lda     sp,x
         sty     $FFFF
         cli                     ; Allow interrupts
 
-; Clear the BSS data
+; Clear the BSS data.
 
         jsr     zerobss
 
-; Initialize irqcount, which means that from now own custom linked in IRQ
-; handlers (via condes) will be called.
+; Initialize irqcount, which means that, from now on, custom linked-in IRQ
+; handlers will be called (via condes).
 
         lda     #.lobyte(__INTERRUPTOR_COUNT__*2)
         sta     irqcount
 
-; Call module constructors
+; Call the module constructors.
 
         jsr     initlib
 
-; Push arguments and call main()
+; Push the command-line arguments; and, call main().
 
         jsr     callmain
 
-; Back from main (this is also the _exit entry). Run module destructors.
+; Back from main() [this is also the exit() entry]. Run the module destructors.
 
 _exit:  pha                     ; Save the return code
         jsr     donelib         ; Run module destructors
 
-; Disable chained IRQ handlers
+; Disable the chained IRQ handlers.
 
         lda     #0
         sta     irqcount        ; Disable custom IRQ handlers
 
-; Copy back the zero page stuff
+; Copy back the zero-page stuff.
 
         ldx     #zpspace-1
 L2:     lda     zpsave,x
@@ -103,28 +103,28 @@ L2:     lda     zpsave,x
         dex
         bpl     L2
 
-; Place the program return code into ST
+; Place the program return code into BASIC's status variable.
 
         pla
         sta     ST
 
-; Restore the stack pointer
+; Restore the stack pointer.
 
         ldx     spsave
         txs
 
-; Enable the ROM and return to BASIC
+; Enable the ROM; and, return to BASIC.
 
         sta     ENABLE_ROM
         rts
 
 ; ------------------------------------------------------------------------
-; IRQ handler. The handler in the ROM enables the kernal and jumps to
-; $CE00, where the ROM code checks for a BRK or IRQ and branches via the
+; IRQ handler. The handler in the ROM enables the Kernal, and jumps to
+; $CE00, where the ROM code checks for a BRK or IRQ, and branches via the
 ; indirect vectors at $314/$316.
 ; To make our stub as fast as possible, we skip the whole part of the ROM
-; handler and jump to the indirect vectors directly. We do also call our
-; own interrupt handlers if we have any, so they need not use $314.
+; handler, and jump to the indirect vectors directly. We do also call our
+; own interrupt handlers if we have any; so, they need not use $314.
 
 .segment        "LOWCODE"
 
@@ -139,7 +139,7 @@ IRQ:    cld                     ; Just to be sure
         and     #$10            ; Test for BRK bit
         bne     dobreak
 
-; It's an IRQ and RAM is enabled. If we have handlers, call them. We will use
+; It's an IRQ; and, RAM is enabled. If we have handlers, call them. We will use
 ; a flag here instead of loading __INTERRUPTOR_COUNT__ directly, since the
 ; condes function is not reentrant. The irqcount flag will be set/reset from
 ; the main code, to avoid races.
@@ -149,8 +149,8 @@ IRQ:    cld                     ; Just to be sure
         jsr     callirq_y       ; Call the IRQ functions
 
 ; Since the ROM handler will end with an RTI, we have to fake an IRQ return
-; on stack, so we get control of the CPU after the ROM handler and can switch
-; back to RAM.
+; on the stack, so that we get control of the CPU after the ROM handler,
+; and can switch back to RAM.
 
 @L1:    lda     #>irq_ret       ; Push new return address
         pha
@@ -161,7 +161,7 @@ IRQ:    cld                     ; Just to be sure
         pha                     ; Push faked X register
         pha                     ; Push faked Y register
         sta     ENABLE_ROM      ; Switch to ROM
-        jmp     (IRQVec)        ; Jump indirect to kernal irq handler
+        jmp     (IRQVec)        ; Jump indirect to Kernal IRQ handler
 
 irq_ret:
         sta     ENABLE_RAM      ; Switch back to RAM
@@ -177,7 +177,7 @@ dobreak:
         beq     nohandler
         jmp     brk_jmp         ; Jump to the handler
 
-; No break handler installed, jump to ROM
+; No break handler installed, jump to ROM.
 
 nohandler:
         sta     ENABLE_ROM