From b7dee84390a08a1ebf2c19b58311ac0b33490768 Mon Sep 17 00:00:00 2001
From: FeralChild64 <you@example.com>
Date: Sun, 26 Jul 2020 22:03:06 +0200
Subject: [PATCH] added memory checks and some other bits to array creation
 routine

---
 src/basic/engine_variables/array_create.s     | 102 ++++++++++--------
 .../helper_array_create_checkmem.s            |  62 +++++++++++
 .../helper_array_create_mul.s                 |  32 +++---
 3 files changed, 133 insertions(+), 63 deletions(-)
 create mode 100644 src/basic/engine_variables/helper_array_create_checkmem.s

diff --git a/src/basic/engine_variables/array_create.s b/src/basic/engine_variables/array_create.s
index d63106e9..46026364 100644
--- a/src/basic/engine_variables/array_create.s
+++ b/src/basic/engine_variables/array_create.s
@@ -88,14 +88,21 @@ array_create_store_dims:
 	phx_trash_a
 	jsr varstr_garbage_collect
 
-	// __FAC1+0/+1 will be used to calculate number of elements
+	// __FAC1+1/+2 will be used to calculate number of elements
 
 	ldy #$01
-	sty __FAC1+0
-	dey
 	sty __FAC1+1
+	dey
+	sty __FAC1+2
 
-	// Create the initial array structure (format checked by creating arrays with original ROM)
+	// Check if there is enough free memory for the header
+
+	pla                                          // .A - number of dimensions
+	sta __FAC1+0
+	jsr helper_array_create_checkmem
+	lda __FAC1+0
+
+	// Create the initial array structure (header) - format checked by creating arrays with original ROM
 
 	// Bytes 0/1 - array name, but we can not fetch it easily now, so skip it for now
 	// Bytes 2/3 - offset to the next array, skip it for now too
@@ -103,13 +110,15 @@ array_create_store_dims:
 	// Bytes 5+  - max index in each dimension (big endian!), this will be set in a loop
 
 	ldy #$04
-	pla
 
 #if CONFIG_MEMORY_MODEL_60K
 	
-	// XXX
-	// XXX: implement this
-	// XXX
+	stx INDEX+2
+
+	ldx #<STREND
+	jsr poke_under_roms
+
+	ldx INDEX+2
 
 #else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
 
@@ -118,7 +127,7 @@ array_create_store_dims:
 #endif
 
 	iny                                          // .Y - index to store dimension sizes
-	tax                                          // .X - dimensions not sotred yet
+	tax                                          // .X - dimensions not stored yet
 
 	// FALLTROUGH
 
@@ -126,19 +135,29 @@ array_create_store_loop:
 
 #if CONFIG_MEMORY_MODEL_60K
 	
-	// XXX
-	// XXX: implement this
-	// XXX
+	stx INDEX+2
+	ldx #<STREND
+
+	pla
+	jsr poke_under_roms
+	sta __FAC1+4
+	iny
+	pla
+	jsr poke_under_roms
+	sta __FAC1+3
+	iny
+
+	ldx INDEX+2
 
 #else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
 
 	pla
 	sta (STREND), y
-	sta __FAC1+3
+	sta __FAC1+4
 	iny
 	pla
 	sta (STREND), y
-	sta __FAC1+2
+	sta __FAC1+3
 	iny
 
 #endif
@@ -156,12 +175,14 @@ array_create_store_dims_done:
 
 	pha
 	sta FOUR6 // XXX do we need to store this value in FOUR6? is it still needed?
-	sta __FAC1+2
-	stx __FAC1+3                       // .X is 0 at this point
+	sta __FAC1+3
+	stx __FAC1+4                       // .X is 0 at this point
 
 	jsr helper_array_create_mul
 
-	// XXX check if we have enough memory
+	// Check if there is enough free memory
+
+	jsr helper_array_create_checkmem
 
 	// Retrieve and store array name
 
@@ -169,9 +190,13 @@ array_create_store_dims_done:
 
 #if CONFIG_MEMORY_MODEL_60K
 	
-	// XXX
-	// XXX: implement this
-	// XXX
+	ldx #<STREND
+
+	pla
+	jsr poke_under_roms
+	iny
+	pla
+	jsr poke_under_roms
 
 #else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
 
@@ -188,33 +213,20 @@ array_create_store_dims_done:
 	lda #$02
 	jsr helper_INDEX_up_A
 
-#if CONFIG_MEMORY_MODEL_60K
-	
-	// XXX
-	// XXX: implement this
-	// XXX
-
-#elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
-
-	// XXX
-	// XXX: implement this
-	// XXX
-
-#else // CONFIG_MEMORY_MODEL_38K
-
-	ldy #$04
-	lda (STREND), y
-
-#endif
-
+	lda __FAC1+0
 	asl
 	jsr helper_INDEX_up_A
 
 #if CONFIG_MEMORY_MODEL_60K
+
+	// .X already contains STREND
 	
-	// XXX
-	// XXX: implement this
-	// XXX
+	ldy #$02
+	lda INDEX+0
+	jsr poke_under_roms
+	iny
+	lda INDEX+1
+	jsr poke_under_roms
 
 #else // CONFIG_MEMORY_MODEL_38K || CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
 
@@ -227,11 +239,7 @@ array_create_store_dims_done:
 
 #endif
 
-	// Clear newly alocated area
-
-	// XXX implement this
-
-	// Adjust STREND
+	// Clear newly alocated area, adjust STREND
 
 	// XXX implement this
 
diff --git a/src/basic/engine_variables/helper_array_create_checkmem.s b/src/basic/engine_variables/helper_array_create_checkmem.s
new file mode 100644
index 00000000..95e68001
--- /dev/null
+++ b/src/basic/engine_variables/helper_array_create_checkmem.s
@@ -0,0 +1,62 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Checks if there is enough memory free for array
+//
+// Input:
+// __FAC1+0    - number of dimensions
+// __FAC1+1/+2 - bytes needed for storage
+//
+// Uses INDEX+2/+3, preserves .X and .Y
+//
+
+
+helper_array_create_checkmem:
+
+	// First calculate FRETOP - STREND
+
+	sec
+	lda FRETOP+0
+	sbc STREND+0
+	sta INDEX+2
+	lda FRETOP+1
+	sbc STREND+1
+	sta INDEX+3
+	bcc helper_array_create_checkmem_fail
+
+	// INDEX+2/+3 contains the amount of memory left, subtract the space needed for storage
+
+	lda INDEX+2
+	sbc __FAC1+1
+	sta INDEX+2
+	lda INDEX+3
+	sbc __FAC1+2
+	sta INDEX+3
+	bcc helper_array_create_checkmem_fail
+
+	// If high byte (INDEX+3) > 0, then we certainly have enough space
+
+	lda INDEX+3
+	bne helper_array_create_checkmem_success
+
+	// We have very little memory left - we need at least number of dimensions*2 + 5 bytes
+
+	lda __FAC1+0
+	asl
+	clc
+	adc #$04
+
+	cmp INDEX+2
+	bcs helper_array_create_checkmem_fail
+
+	// FALLTROUGH
+
+helper_array_create_checkmem_success:
+
+	rts
+
+helper_array_create_checkmem_fail:
+
+	jmp do_OUT_OF_MEMORY_error
diff --git a/src/basic/engine_variables/helper_array_create_mul.s b/src/basic/engine_variables/helper_array_create_mul.s
index 1d42e218..b0424f44 100644
--- a/src/basic/engine_variables/helper_array_create_mul.s
+++ b/src/basic/engine_variables/helper_array_create_mul.s
@@ -2,7 +2,7 @@
 // #LAYOUT# *   BASIC_0 #TAKE
 // #LAYOUT# *   *       #IGNORE
 
-// 16-bit multiplication, INDEX+0/+1 = __FAC1+0/+1 * __FAC1+2/+3; __FAC1+0/+1 = INDEX+0/+1
+// 16-bit multiplication, INDEX+0/+1 = __FAC1+1/+2 * __FAC1+3/+4; __FAC1+1/+2 = INDEX+0/+1
 // uses INDEX+2/+3 (for helper routine) as work area
 
 
@@ -12,37 +12,37 @@ helper_array_create_mul: // preserves .X and .Y
 
 	// We will reuse 8x8 multiplication routine used by floating point operations
 
-	// __FAC1+0 (lo byte) * __FAC1+2 (lo byte)
+	// __FAC1+1 (lo byte) * __FAC1+3 (lo byte)
 
-	lda __FAC1+0
+	lda __FAC1+1
 	sta INDEX+2
-	lda __FAC1+2
+	lda __FAC1+3
 	jsr mul_FAC2_FAC1_8x8                        // this preserves .Y
 
 	sta INDEX+0                                  // result - lo byte
 	stx INDEX+1                                  // result - hi byte
 
-	// __FAC1+0 (lo byte) * __FAC1+3 (hi byte)
-
-	lda __FAC1+0
-	sta INDEX+2
-	lda __FAC1+3
-	jsr helper_array_create_mul_8x8_add          // multiply and add to high byte of the result
-
-	// __FAC1+1 (hi byte) * __FAC1+2 (lo byte)
+	// __FAC1+1 (lo byte) * __FAC1+4 (hi byte)
 
 	lda __FAC1+1
 	sta INDEX+2
-	lda __FAC1+2
+	lda __FAC1+4
 	jsr helper_array_create_mul_8x8_add          // multiply and add to high byte of the result
 
-	// __FAC1+1 (hi byte) * __FAC1+3 (hi byte) has to be 0,
+	// __FAC1+2 (hi byte) * __FAC1+3 (lo byte)
+
+	lda __FAC1+2
+	sta INDEX+2
+	lda __FAC1+3
+	jsr helper_array_create_mul_8x8_add          // multiply and add to high byte of the result
+
+	// __FAC1+2 (hi byte) * __FAC1+4 (hi byte) has to be 0,
 	// otherwise the result would be out of range
 	// do not calculate
 
-	lda __FAC1+0
+	lda __FAC1+2
 	beq helper_array_create_mul_success
-	lda __FAC1+3
+	lda __FAC1+4
 	beq helper_array_create_mul_success
 
 	// FALLTROUGH