remove eval stack references from p8 code

compiler/res/prog8lib/c128/syslib.p8

@@ -446,10 +446,6 @@ _irq_handler_init
 		sta  IRQ_SCRATCH_ZPWORD2
 		lda  P8ZP_SCRATCH_W2+1
 		sta  IRQ_SCRATCH_ZPWORD2+1
-		; Set X to the bottom 32 bytes of the evaluation stack, to HOPEFULLY not clobber it.
-		; This leaves 128-32=96 stack entries for the main program, and 32 stack entries for the IRQ handler.
-		; We assume IRQ handlers don't contain complex expressions taking up more than that.
-		ldx  #32
 		cld
 		rts
 
@@ -774,7 +770,7 @@ cx16 {
     ; the sixteen virtual 16-bit registers that the CX16 has defined in the zeropage
     ; they are simulated on the C128 as well but their location in memory is different
     ; (because there's no room for them in the zeropage)
-    ; $1300-$1bff is unused RAM on C128. We'll use $1a00-$1bff as the lo/hi evalstack.
+    ; $1300-$1bff is unused RAM on C128.
     &uword r0  = $1be0
     &uword r1  = $1be2
     &uword r2  = $1be4

compiler/res/prog8lib/c64/syslib.p8

@@ -413,10 +413,6 @@ _irq_handler_init
 		sta  IRQ_SCRATCH_ZPWORD2
 		lda  P8ZP_SCRATCH_W2+1
 		sta  IRQ_SCRATCH_ZPWORD2+1
-		; Set X to the bottom 32 bytes of the evaluation stack, to HOPEFULLY not clobber it.
-		; This leaves 128-32=96 stack entries for the main program, and 32 stack entries for the IRQ handler.
-		; We assume IRQ handlers don't contain complex expressions taking up more than that.
-		ldx  #32
 		cld
 		rts
 

compiler/res/prog8lib/cx16/syslib.p8

@@ -855,10 +855,6 @@ _irq_handler_init
 		sta  IRQ_SCRATCH_ZPWORD2
 		lda  P8ZP_SCRATCH_W2+1
 		sta  IRQ_SCRATCH_ZPWORD2+1
-		; Set X to the bottom 32 bytes of the evaluation stack, to HOPEFULLY not clobber it.
-		; This leaves 128-32=96 stack entries for the main program, and 32 stack entries for the IRQ handler.
-		; We assume IRQ handlers don't contain complex expressions taking up more than that.
-		ldx  #32
 		cld
 		rts
 

compiler/res/prog8lib/test_stack.p8

@@ -1,4 +1,4 @@
-; utility debug code to print the X (evalstack) and SP (cpu stack) registers.
+; utility debug code to print the SP (cpu stack pointer) register.
 
 %import textio
 
@@ -7,7 +7,6 @@ test_stack {
 
     asmsub test() {
         %asm {{
-	stx  _saveX
 	lda  #13
 	jsr  txt.chrout
 	lda  #'-'
@@ -17,14 +16,6 @@ test_stack {
 	bne  -
 	lda  #13
 	jsr  txt.chrout
-	lda  #'x'
-	jsr  txt.chrout
-	lda  #'='
-	jsr  txt.chrout
-	lda  _saveX
-	jsr  txt.print_ub
-	lda  #' '
-	jsr  txt.chrout
 	lda  #'s'
 	jsr  txt.chrout
 	lda  #'p'
@@ -43,9 +34,7 @@ test_stack {
 	bne  -
 	lda  #13
 	jsr  txt.chrout
-	ldx  _saveX
 	rts
-_saveX	.byte 0
         }}
     }
 }

docs/source/todo.rst

@@ -1,12 +1,12 @@
 TODO
 ====
 
-- (branch): remove all evalstack references from p8 code files
 - (branch): remove all evalstack references from asm code files
 - (branch): remove ExpressionsAsmGen.kt altogether
 - (branch): clean up all X register special handling
 - (branch): fix optimizeCmpSequence in AsmOptimizer
 - (branch): fix inplaceModification TODO in AugmentableAssignmentAsmGen
+- (branch): fix up cx16/keyboardhandler.p8 X register shenanigans
 - (branch): clean up docs about eval stack and X register
 
 - IR: instructions that do type conversion (SZ etc, CONCAT, SGN) should put the result in a DIFFERENT register.