diff lab4/test/sumpower.p @ 0:bfdcc3820b32

Basis
author Mike Spivey <mike@cs.ox.ac.uk>
date Thu, 05 Oct 2017 08:04:15 +0100
parents
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lab4/test/sumpower.p	Thu Oct 05 08:04:15 2017 +0100
@@ -0,0 +1,131 @@
+(* Higher-order functions *)
+
+proc sum(a, b: integer; proc f(x: integer): integer): integer;
+  var i, s: integer;
+begin
+  i := a; s := 0;
+  while i <= b do
+    s := s + f(i);
+    i := i + 1
+  end;
+  return s
+end;
+
+proc sum_powers(a, b, n: integer): integer;
+  proc pow(x: integer): integer;
+    var j, p: integer;
+  begin
+    j := 0; p := 1;
+    while j < n do
+      p := p * x;
+      j := j + 1
+    end;
+    return p
+  end;
+begin
+  return sum(a, b, pow)
+end;
+
+begin
+  print_num(sum_powers(1, 10, 3));
+  newline()
+end.
+
+(*<<
+3025
+>>*)
+
+(*[[
+@ picoPascal compiler output
+	.include "fixup.s"
+	.global pmain
+
+@ proc sum(a, b: integer; proc f(x: integer): integer): integer;
+	.text
+_sum:
+	mov ip, sp
+	stmfd sp!, {r0-r3}
+	stmfd sp!, {r4-r10, fp, ip, lr}
+	mov fp, sp
+@   i := a; s := 0;
+	ldr r4, [fp, #40]
+	mov r5, #0
+.L2:
+@   while i <= b do
+	ldr r0, [fp, #44]
+	cmp r4, r0
+	bgt .L4
+@     s := s + f(i);
+	mov r0, r4
+	ldr r10, [fp, #52]
+	ldr r1, [fp, #48]
+	blx r1
+	add r5, r5, r0
+@     i := i + 1
+	add r4, r4, #1
+	b .L2
+.L4:
+@   return s
+	mov r0, r5
+	ldmfd fp, {r4-r10, fp, sp, pc}
+	.ltorg
+
+@ proc sum_powers(a, b, n: integer): integer;
+_sum_powers:
+	mov ip, sp
+	stmfd sp!, {r0-r3}
+	stmfd sp!, {r4-r10, fp, ip, lr}
+	mov fp, sp
+@   return sum(a, b, pow)
+	mov r3, fp
+	set r2, _pow
+	ldr r1, [fp, #44]
+	ldr r0, [fp, #40]
+	bl _sum
+	ldmfd fp, {r4-r10, fp, sp, pc}
+	.ltorg
+
+@   proc pow(x: integer): integer;
+_pow:
+	mov ip, sp
+	stmfd sp!, {r0-r1}
+	stmfd sp!, {r4-r10, fp, ip, lr}
+	mov fp, sp
+@     j := 0; p := 1;
+	mov r4, #0
+	mov r5, #1
+.L7:
+@     while j < n do
+	ldr r0, [fp, #24]
+	ldr r0, [r0, #48]
+	cmp r4, r0
+	bge .L9
+@       p := p * x;
+	ldr r0, [fp, #40]
+	mul r5, r5, r0
+@       j := j + 1
+	add r4, r4, #1
+	b .L7
+.L9:
+@     return p
+	mov r0, r5
+	ldmfd fp, {r4-r10, fp, sp, pc}
+	.ltorg
+
+pmain:
+	mov ip, sp
+	stmfd sp!, {r4-r10, fp, ip, lr}
+	mov fp, sp
+@   print_num(sum_powers(1, 10, 3));
+	mov r2, #3
+	mov r1, #10
+	mov r0, #1
+	bl _sum_powers
+	bl print_num
+@   newline()
+	bl newline
+	ldmfd fp, {r4-r10, fp, sp, pc}
+	.ltorg
+
+@ End
+]]*)