Add parsers for basic instruction typesHEADmaster

4 files changed, 22 insertions, 13 deletions

diff --git a/newasm/parsers/decimal.s b/newasm/parsers/decimal.s
index a1516d2..cc9dff4 100644
--- a/newasm/parsers/decimal.s
+++ b/newasm/parsers/decimal.s
@@ -5,8 +5,6 @@
 .type decimal, %function
 .global decimal
 
-// 1 not a digit
-
 // R4 input stream
 // R2 output value
 
@@ -35,5 +33,5 @@ loop:     LDRB    R0, [R4]    // get another char
           MULS    R2, R3      // shift result by one decimal place
           ADDS    R2, R0      // accumulate into R2
           B       loop        // keep getting digits
-bad:      MOVS    R0, #1      // return code 1 (not a digit)
+bad:      MOVS    R0, #5      // return code 5 (not a digit)
           BX      LR
diff --git a/newasm/parsers/immediate.s b/newasm/parsers/immediate.s
new file mode 100644
index 0000000..ac3e578
--- /dev/null
+++ b/newasm/parsers/immediate.s
@@ -0,0 +1,13 @@
+.syntax unified
+.cpu cortex-m0plus
+.thumb
+
+.type immediate, %function
+.global immediate
+
+// R4 input buffer
+// R2 output buffer
+
+immediate:PUSH    {LR}
+          BL      decimal
+          POP     {PC}
diff --git a/newasm/parsers/label.s b/newasm/parsers/label.s
index 4770e6c..45d39e5 100644
--- a/newasm/parsers/label.s
+++ b/newasm/parsers/label.s
@@ -5,9 +5,6 @@
 .type label, %function
 .global label
 
-// 1 unexpected begin char
-// 2 doesn't end with colon
-
 // R4 input buffer
 // R2 output buffer
 
@@ -23,7 +20,7 @@ label:    PUSH    {LR}
           LDRB    R0, [R4]    // get a char
           CMP     R0, ':      // colon
           BEQ     3f
-          MOVS    R0, #2      // return code 2 (expected colon)
+          MOVS    R0, #3      // return code 3 (expected colon)
           POP     {PC}
 3:        ADDS    R4, 1       // consume the colon
           MOVS    R0, #0      // return code 0 (success)
diff --git a/newasm/parsers/register.s b/newasm/parsers/register.s
index 48ebf7a..9334aa3 100644
--- a/newasm/parsers/register.s
+++ b/newasm/parsers/register.s
@@ -5,9 +5,6 @@
 .type register, %function
 .global register
 
-// 1 unexpected char
-// 2 invalid general-purpose register number
-
 // R4 input buffer
 // R2 output buffer
 
@@ -21,9 +18,12 @@ r_test:   CMP     R0, 'R
           POP     {PC}        // error code already in R0
 validate: CMP     R2, #12     // general purpose registers 0-12
           BLS     success
-          MOVS    R0, #2      // invalid register number error code
+          MOVS    R0, #7      // invalid register number error code
           POP     {PC}
-special:  LDRH    R0, [R4]      // get two bytes from input stream
+special:  LDRB    R0, [R4]      // get two bytes from input stream
+          LDRB    R1, [R4, 1]
+          LSLS    R1, 8
+          ORRS    R0, R1
           ADR     R2, table     // get address of table
           MOVS    R3, 0         // set table offset to 0
 loop:     LDRH    R1, [R2, R3]  // get two bytes from table at current offset
@@ -32,7 +32,7 @@ loop:     LDRH    R1, [R2, R3]  // get two bytes from table at current offset
           ADDS    R3, 2         // increment table offset
           CMP     R3, 6         // compare offset to table size
           BLO     loop          // loop until end of table
-          MOVS    R0, #1        // return code 1 (unexpected char)
+          MOVS    R0, #6        // return code 6 (expected register)
           POP     {PC}
 done:     ADDS    R4, 2         // consume two chars
           LSRS    R3, 1         // divide table offset by two to row
@@ -41,6 +41,7 @@ done:     ADDS    R4, 2         // consume two chars
 success:  MOVS    R0, #0        // return code 0 (success)
           POP     {PC}
 
+          .align  4
 table:    .ascii  "SP"
           .ascii  "LR"
           .ascii  "PC"