py/nlrthumb: Convert NLR thumb funcs from asm to C with inline-asm.

Now only the bits that really need to be written in assembler are written
in it, otherwise C is used.  This means that the assembler code no longer
needs to know about the global state structure which makes it much easier
to maintain.

2 files changed, 134 insertions, 165 deletions

diff --git a/py/nlrthumb.S b/py/nlrthumb.S
deleted file mode 100644
index 624275e8ed..0000000000
--- a/py/nlrthumb.S
+++ /dev/null
@@ -1,165 +0,0 @@
-/*
- * This file is part of the MicroPython project, http://micropython.org/
- *
- * The MIT License (MIT)
- *
- * Copyright (c) 2013-2015 Damien P. George
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#if (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
-
-// We only need the functions here if we are on arm/thumb, and we are not
-// using setjmp/longjmp.
-//
-// For reference, arm/thumb callee save regs are:
-//      r4-r11, r13=sp
-
-// the offset of nlr_top within mp_state_ctx_t
-#define NLR_TOP_OFFSET (2 * 4)
-
-    .syntax unified
-    /*.cpu cortex-m4*/
-    /*.thumb*/
-    .text
-    .align  2
-
-/**************************************/
-// mp_uint_t nlr_push(r0=nlr_buf_t *nlr)
-
-    .global nlr_push
-#if defined(__thumb2__)
-    .thumb
-    .thumb_func
-#endif
-    .type   nlr_push, %function
-nlr_push:
-    str     r4, [r0, #12]           @ store r4 into nlr_buf
-    str     r5, [r0, #16]           @ store r5 into nlr_buf
-    str     r6, [r0, #20]           @ store r6 into nlr_buf
-    str     r7, [r0, #24]           @ store r7 into nlr_buf
-
-#if defined(__ARM_ARCH_6M__)
-    mov     r1, r8
-    str     r1, [r0, #28]           @ store r8 into nlr_buf
-    mov     r1, r9
-    str     r1, [r0, #32]           @ store r9 into nlr_buf
-    mov     r1, r10
-    str     r1, [r0, #36]           @ store r10 into nlr_buf
-    mov     r1, r11
-    str     r1, [r0, #40]           @ store r11 into nlr_buf
-    mov     r1, r13
-    str     r1, [r0, #44]           @ store r13=sp into nlr_buf
-    mov     r1, lr
-    str     r1, [r0, #8]            @ store lr into nlr_buf
-#else
-    str     r8, [r0, #28]           @ store r8 into nlr_buf
-    str     r9, [r0, #32]           @ store r9 into nlr_buf
-    str     r10, [r0, #36]          @ store r10 into nlr_buf
-    str     r11, [r0, #40]          @ store r11 into nlr_buf
-    str     r13, [r0, #44]          @ store r13=sp into nlr_buf
-    str     lr, [r0, #8]            @ store lr into nlr_buf
-#endif
-
-    ldr     r3, nlr_top_addr        @ load addr of nlr_top
-    ldr     r2, [r3]                @ load nlr_top
-    str     r2, [r0]                @ store nlr_top into nlr_buf
-    str     r0, [r3]                @ store nlr_buf into nlr_top (to link list)
-
-    movs    r0, #0                  @ return 0, normal return
-    bx      lr                      @ return
-    .size   nlr_push, .-nlr_push
-
-/**************************************/
-// void nlr_pop()
-
-    .global nlr_pop
-#if defined(__thumb2__)
-    .thumb
-    .thumb_func
-#endif
-    .type   nlr_pop, %function
-nlr_pop:
-    ldr     r3, nlr_top_addr        @ load addr of nlr_top
-    ldr     r2, [r3]                @ load nlr_top
-    ldr     r2, [r2]                @ load prev nlr_buf
-    str     r2, [r3]                @ store prev nlr_buf to nlr_top (to unlink list)
-    bx      lr                      @ return
-    .size   nlr_pop, .-nlr_pop
-
-/**************************************/
-// void nlr_jump(r0=mp_uint_t val)
-
-    .global nlr_jump
-#if defined(__thumb2__)
-    .thumb
-    .thumb_func
-#endif
-    .type   nlr_jump, %function
-nlr_jump:
-    ldr     r3, nlr_top_addr        @ load addr of nlr_top
-    ldr     r2, [r3]                @ load nlr_top
-    cmp     r2, #0                  @ test if nlr_top is NULL
-#if defined(__ARM_ARCH_6M__)
-    bne     nlr_jump_non_null       @ if nlr_top is NULL, transfer control to nlr_jump_fail
-    bl      nlr_jump_fail
-nlr_jump_non_null:
-#else
-    beq     nlr_jump_fail           @ if nlr_top is NULL, transfer control to nlr_jump_fail
-#endif
-    str     r0, [r2, #4]            @ store return value
-    ldr     r0, [r2]                @ load prev nlr_buf
-    str     r0, [r3]                @ store prev nol_buf into nlr_top (to unlink list)
-
-    ldr     r4, [r2, #12]           @ load r4 from nlr_buf
-    ldr     r5, [r2, #16]           @ load r5 from nlr_buf
-    ldr     r6, [r2, #20]           @ load r6 from nlr_buf
-    ldr     r7, [r2, #24]           @ load r7 from nlr_buf
-#if defined(__ARM_ARCH_6M__)
-    ldr     r1, [r2, #28]           @ load r8 from nlr_buf
-    mov     r8, r1
-    ldr     r1, [r2, #32]           @ load r9 from nlr_buf
-    mov     r9, r1
-    ldr     r1, [r2, #36]           @ load r10 from nlr_buf
-    mov     r10, r1
-    ldr     r1, [r2, #40]           @ load r11 from nlr_buf
-    mov     r11, r1
-    ldr     r1, [r2, #44]           @ load r13=sp from nlr_buf
-    mov     r13, r1
-    ldr     r1, [r2, #8]            @ load lr from nlr_buf
-    mov     lr, r1
-#else
-    ldr     r8, [r2, #28]           @ load r8 from nlr_buf
-    ldr     r9, [r2, #32]           @ load r9 from nlr_buf
-    ldr     r10, [r2, #36]          @ load r10 from nlr_buf
-    ldr     r11, [r2, #40]          @ load r11 from nlr_buf
-    ldr     r13, [r2, #44]          @ load r13=sp from nlr_buf
-    ldr     lr, [r2, #8]            @ load lr from nlr_buf
-#endif
-
-    movs    r0, #1                  @ return 1, non-local return
-    bx      lr                      @ return
-    .size   nlr_jump, .-nlr_jump
-
-    .align  2
-nlr_top_addr:
-    .word   mp_state_ctx + NLR_TOP_OFFSET
-
-#endif // (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
diff --git a/py/nlrthumb.c b/py/nlrthumb.c
new file mode 100644
index 0000000000..a61c73c036
--- /dev/null
+++ b/py/nlrthumb.c
@@ -0,0 +1,134 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013-2016 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/mpstate.h"
+#include "py/nlr.h"
+
+#if (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))
+
+// We only need the functions here if we are on arm/thumb, and we are not
+// using setjmp/longjmp.
+//
+// For reference, arm/thumb callee save regs are:
+//      r4-r11, r13=sp
+
+__attribute__((naked)) unsigned int nlr_push(nlr_buf_t *nlr) {
+
+    __asm volatile (
+    "str    r4, [r0, #12]       \n" // store r4 into nlr_buf
+    "str    r5, [r0, #16]       \n" // store r5 into nlr_buf
+    "str    r6, [r0, #20]       \n" // store r6 into nlr_buf
+    "str    r7, [r0, #24]       \n" // store r7 into nlr_buf
+
+#if defined(__ARM_ARCH_6M__)
+    "mov    r1, r8              \n"
+    "str    r1, [r0, #28]       \n" // store r8 into nlr_buf
+    "mov    r1, r9              \n"
+    "str    r1, [r0, #32]       \n" // store r9 into nlr_buf
+    "mov    r1, r10             \n"
+    "str    r1, [r0, #36]       \n" // store r10 into nlr_buf
+    "mov    r1, r11             \n"
+    "str    r1, [r0, #40]       \n" // store r11 into nlr_buf
+    "mov    r1, r13             \n"
+    "str    r1, [r0, #44]       \n" // store r13=sp into nlr_buf
+    "mov    r1, lr              \n"
+    "str    r1, [r0, #8]        \n" // store lr into nlr_buf
+#else
+    "str    r8, [r0, #28]       \n" // store r8 into nlr_buf
+    "str    r9, [r0, #32]       \n" // store r9 into nlr_buf
+    "str    r10, [r0, #36]      \n" // store r10 into nlr_buf
+    "str    r11, [r0, #40]      \n" // store r11 into nlr_buf
+    "str    r13, [r0, #44]      \n" // store r13=sp into nlr_buf
+    "str    lr, [r0, #8]        \n" // store lr into nlr_buf
+#endif
+
+    "b      nlr_push_tail       \n" // do the rest in C
+    );
+
+    return 0; // needed to silence compiler warning
+}
+
+unsigned int nlr_push_tail(nlr_buf_t *nlr) {
+    nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
+    nlr->prev = *top;
+    *top = nlr;
+    return 0; // normal return
+}
+
+void nlr_pop(void) {
+    nlr_buf_t **top = &MP_STATE_THREAD(nlr_top);
+    *top = (*top)->prev;
+}
+
+NORETURN __attribute__((naked)) void nlr_jump(void *val) {
+    nlr_buf_t **top_ptr = &MP_STATE_THREAD(nlr_top);
+    nlr_buf_t *top = *top_ptr;
+    if (top == NULL) {
+        nlr_jump_fail(val);
+    }
+
+    top->ret_val = val;
+    *top_ptr = top->prev;
+
+    __asm volatile (
+    "mov    r0, %0              \n" // r0 points to nlr_buf
+    "ldr    r4, [r0, #12]       \n" // load r4 from nlr_buf
+    "ldr    r5, [r0, #16]       \n" // load r5 from nlr_buf
+    "ldr    r6, [r0, #20]       \n" // load r6 from nlr_buf
+    "ldr    r7, [r0, #24]       \n" // load r7 from nlr_buf
+
+#if defined(__ARM_ARCH_6M__)
+    "ldr    r1, [r0, #28]       \n" // load r8 from nlr_buf
+    "mov    r8, r1              \n"
+    "ldr    r1, [r0, #32]       \n" // load r9 from nlr_buf
+    "mov    r9, r1              \n"
+    "ldr    r1, [r0, #36]       \n" // load r10 from nlr_buf
+    "mov    r10, r1             \n"
+    "ldr    r1, [r0, #40]       \n" // load r11 from nlr_buf
+    "mov    r11, r1             \n"
+    "ldr    r1, [r0, #44]       \n" // load r13=sp from nlr_buf
+    "mov    r13, r1             \n"
+    "ldr    r1, [r0, #8]        \n" // load lr from nlr_buf
+    "mov    lr, r1              \n"
+#else
+    "ldr    r8, [r0, #28]       \n" // load r8 from nlr_buf
+    "ldr    r9, [r0, #32]       \n" // load r9 from nlr_buf
+    "ldr    r10, [r0, #36]      \n" // load r10 from nlr_buf
+    "ldr    r11, [r0, #40]      \n" // load r11 from nlr_buf
+    "ldr    r13, [r0, #44]      \n" // load r13=sp from nlr_buf
+    "ldr    lr, [r0, #8]        \n" // load lr from nlr_buf
+#endif
+    "movs   r0, #1              \n" // return 1, non-local return
+    "bx     lr                  \n" // return
+    :                               // output operands
+    : "r"(top)                      // input operands
+    :                               // clobbered registers
+    );
+
+    for (;;); // needed to silence compiler warning
+}
+
+#endif // (!defined(MICROPY_NLR_SETJMP) || !MICROPY_NLR_SETJMP) && (defined(__thumb2__) || defined(__thumb__) || defined(__arm__))